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TM 5-4210-227-24&P-3

1. 2 5 FORWARD CLUTCH AND TURBINE SHAFT a Function Differs Among VOCS E b Description 2 6 C Operation 2 6 2 12 FOURTH CLUTCH a Function Differs Among Je m 2 6 b Description 2 6 C Operation 2 6 Copyright 1983 General Motors Corp Paragraph Page SECOND THIRD CLUTCHES AND CENTER SUPPORT a Function Differs Among elo ess 2 7 b Description C Operation of Third Clutch 2 7 d Operation of Second ecl 2 7 2 14 FIRST CLUTCH a Function Differs Among Meo cm M 2 8 b Description 2 8 c Operation HT 740D IBN TD Hi 2 8 d Operation HT 750CRD HT OA GAD PR 2 8 e Operation HT 750DRD 2 8 2 15 LOW CLUTCH a Function Differs Among Models 2 8 b Description eee 2 9 C Operation HT 750CRD HT 754GRD eise tentes 2 9 d Operation HT 750DRD 2 9 2 161 PLANETARY GEARING 740D HT 747D a Description 2 9 b Operation 2 9 2 17 PLANETARY GEARING HT 750CRD
2. 6 19 6 11 CONVERTER HOUSING WITH 2 BOLT TOP COVER RETARDER PLATE OIL PUMP a Disassembly 6 21 b 6 22 6 12 CONVERTER HOUSING WITH 8 BOLT TOP COVER RETARDER PLATE OIL PUMP a Disassembly 6 23 b Assembly 6 24 6 13 CONVERTER HOUSING WITH 8 BOLT TOP COVER FRONT SUPPORT OIL PUMP a Disassembly 6 25 b Assembly 6 25 6 14 SCAVENGE OIL PUMP PTO IDLER GEAR a b Machining Driven Gear BUSING M 6 26 c Assembly 6 26 6 15 RETARDER VALVE BODY ASSEMBLY Disassembly 6 26 Assembly 6 26 D Copyright 1983 General Motors Corp Paragraph Page RETARDER HOUSING FRONT SUPPORT a lt D ASSOMDIY i sonent kd 6 28 6 17 FORWARD CLUTCH AND TURBINE SHAFT a lt b Assembly 6 30 FOURTH CLUTCH ASSEMBLY a Disassembly
3. 7 25 b Stator Assembly 7 27 7 16 INSTALLING VALVE BODY OIL FILTER OIL PAN HT 740D HT 747D a Valve Body 7 27 b Oil Filter Oil 7 28 7 17 INSTALLING VALVE BODIES FILTER OIL PAN HT 750CRD HT 754CRD HT 750DRD DRD DB a Valve Bodies 7 29 b Oil Filter Oil 7 31 7 18 INSTALLING FLYWHEEL LOCKUP CLUTCH TORQUE CONVERTER TURBINE a Align Flywheel for Installation 7 31 b Installation eeeen 7 31 c Transmission Front Cover 7 32 7 19 INSTALLING EXTERNAL COMPONENTS a External Components b Retarder Valve Body 7 34 TABLE OF CONTENTS cont Paragraph Page 7 20 INSTALLATION OF TRANSFER GEAR HOUSING ADAPTER ASSEMBLY TRANSFER GEAR HOUSING DISCONNECT CLUTCHES OUTPUT INPUT FLANGES a Transfer Gear Housing Adapter Assembly 7 34 b Transfer Gear Housing aere d TE 7 34 Output Manual Disconnect AEE E E 7 35 d Installing Output Input me S oriek REEERE REREN 35 e Bearing Retainer amp Cover 7 35 7 21 REMOVING TRANSMISSION FROM OVERHAUL
4. 3 12 D OI 3 12 3 12 TRANSMISSION STALL TEST du Cir inivenesiccuncssnnnnbanenentencnnebunnbunbioa 3 13 ME Procedu gt 3 13 3 13 PRESERVATION AND STORAGE a Storage New Transmission prior to installation 3 13 b Preservation Methods 3 14 c Storage One Year Without 3 14 d Storage One Year ico 3 14 e Restoring Transmission to ie MERE 3 15 3 14 RETAINING OUTPUT FLANGE 3 15 3 15 OUTPUT SEAL AND BEARING REPLACEMENT IN VEHICLE a 3 15 b Installation eese 3 16 3 16 REPLACING MANUAL DISCONNECT OUTPUT SEAL a Remove 3 16 b Install 3 16 3 17 CHECKING OIL PRESSURES 3 18 TROUBLESHOOTING BEFORE REMOVAL OR OPERATION a Visual Inspection 3 17 b System Knowledge 3 17 Paragraph Page TROUBLESHOOTING DURING OPERATION a Determine Trouble Cause 3 17 b Properly Tuned Engine 3 17 TROUBLESHOOTING AFTER REMOVAL 3 17 TROUBLESHOOTING 3 17 GENERAL OVERHAUL INFORMATION 4 TISCOPE
5. 6 53 TABLE OF CONTENTS cont Paragraph Page 6 27 TRANSMISSION HOUSING Disassembly m 6 56 nicis Me 6 56 6 2 TRANSFER GEAR HOUSING AND GEARS Disassembly Assembly essere 6 59 2 1 o P amp 6 30 O w 6 31 O w 6 32 6 33 2909 e f TRANSFER GEAR HOUSING ADAPTER OUTPUT SHAFTS Disassembly 6 62 Assembly 6 62 FLEX DISK ASSEMBLY Disassembly Assembly re 6 63 GOVERNOR Disassembly 6 64 Assembly 6 64 OUTPUT MANUAL DISCONNECT ASSEMBLIES Disassembly 6 64 Assembly 6 65 ESTABLISHING CLUTCH CLEARANCES Two Methods eene 6 66 Forward Clutch cseeeeeeeecceeeeeeeeees 6 66 Fourth Clutch sese esee 6 66 First Clutch HT 740 Low Clutch HT 750 6 67 First Clutch HT 750 Second and Third Clutches 6 68 ASSEMBLY OF TRANSMISSION 7 1 SCOPE cccccccceccccecceececeeseeceeeeeeteceeentseees 7 1 7 2 CLUTCH CLEARANCES a b Preparation Procedure
6. ae cer unit MAIN SHAFT aep TRANSMISSION ADAPTER HOUSING M BOLT 12 12 X 5 3 4 2 M a2 Sey Fig 5 49 Removing gear unit assembly HT 750CRD HT 754CRD 4 Lift careful straight upward on the lifting bracket to remove the center support assembly CAUTION The center support is fitted to the transmission housing with very little clearance It may bind in the housing if the housing is cold Heat the housing slightly if necessary Do not use a torch to heat the housing A heat lamp or a current of warm air is sufficient If the support assembly starts upward and then binds tap it downward and lift again 5 Refer td paragraph 6 19 for rebuild of the center support assembly rag J 24208 3 Copyright 1983 General Motors Corp 5 21 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 6 Attach lifting bracket J 24196 to the main shaft of the gear unit assembly 5 49 7 Attach a hoist to the lifting bracket eyebolt and remove the gear unit and shaft assembly from the transmission housing fig 5 49 8 Refer to paragraph 6 22 for rebuild of the gear unit and shaft assembly 9 Remove the snapring that retains the second clutch plates fig 5 41 Remove the 13 second clutch plates NOTE Tie the second clutch plates together and identify the pack Retain for inspection 10 Invert the transmission housing rear end upward and remove the two bolts
7. FOURTH CLUTCH HOLD REGULATOR VALVE THIRD AND FOURTH CLUTCH FEED REVERSE ix SIGNAL 4 mm mm EN me LOWCLUTCH SS SANS VALVE ESSE tee 227 Wi 1 EE RAN NS LIE ade i NEJN pm p REAR GOVERNOR VALVE J A ORIFICE WS GOVERNOR ACCUMULATOR S SECOND CLUTCH FOURTH CLUTCH TRIMMER VALVE TRIMMER VALVE E And ae THIRD CLUTCH TRIMMER VALVE TRIMMER REGULATOR 3961 Foldout 8 Model HT 750DRD transmission hydraulic system all range lockup schematic view Copyright 1983 General Motors Corp FOLDOUT 8 A Self locking bolt 1 2 20 x 1 12 Al 2 Flex disk assembly 3 Flex disk hub assembly 4 Hub 5 Dowel pin 6 Flex disk 7 Flex disk I 8 Flex disk plate 9 Self locking bolt 1 2 20 x 3 4 12 A 10 Flywheel assembly 11 Starter ring gear 12 Flywheel 13 Converter housing adapter HT 750 models 14 Flywheel housing gasket Torque Ib ft Nm A 96 115 130 156 B 1 Nut 2 Washer 3 seal 4 Front cover 5 Gasket 6 Bearing 7 Converter drive cover A Foldout 9 Flex disc and flywheel assemblies exploded view HT 740 HT750D AUTOMATIC TRANSMISSIONS B Foldout 9 Transmission front cover remote mount exploded view Copyright 1983 General Motors Corp FOLDOUT 9 HT 74
8. LIFTING BRACKET OUTPUT SHAFT REAR COVER BALL BEARING H LOW RING GEAR HOUSING 52991 Fig 5 51 Removing rear cover assembly HT 750DRD 3 Attach a hoist to the lifting bracket fastened to output shaft and carefully separate the rear cover from the adapter housing lio 551 Hemove the rear cover gasket 4 Refer to paragraph 6 26 for rebuild of the rear cover assembly Low Planetary and Clutch 1 Remove the low ring gear and ball bearing assembly Remove the ball bearing assembly from the ring gear if bearing replacement is necessary 2 fig 5 52 Remove bearing race from ring gear 3 Remove the bearing race and needle bearing from the low planetary carrier Remove the low planetary carrier assembly fig 5 53 Remove the bear BEARING RACE PLANETARY NAR NEEDLE BEARING CARRIER ASSEMBLY X7 ees lt lt BEARING RACE 52962 Fig 5 52 Removing low ring gear HT 750DRD E m E M LOW PLANETARY Ms i nom e CARRIER ASSEMBLY CLUTCH ADAPTER PLATES 13 HOUSING nA 5253 Fig 5 53 Removing low planetary carrier assembly HT 750DRD ing and bearing races from the low gear hub and gear assembly 5 Remove the low sun gear and hub assembly f 54 Refer td paragraph 24 lor rebuild of the low sun gear and hub assembly 6 Remove seven external tanged and six int
9. ZND GEAR START PI Ie GOVERNOR LATE MODELS HAE j A 2ND CLUTCH 4TH CLUTCH 2 3 ACCUMULATOR Yj udo NA TRIMMER VALVE TRIMMER VALVE RELAY VALVE VALVE CASAS r x fu t pem 34 LOCKUP 1 2 LOCKUP j 27 e CUTOFF VALVE LLLLLL A CUTOFF VALVE TRIM BOOST ix Vo ACCUMULATOR VALVE ESSE 74 LOCKUP CUTOFF VALVES ESSE BYPASS REAR GOVERNOR VALVE EXTERNAL TAP REAR COVER EXTERNAL TAP GOVERNOR PRESSURE REAR COVER GOVERNOR FEED Foldout 5 Model HT 740D HT 747D transmission hydraulic system schematic view Copyright 1983 General Motors Corp MAIN PRESSURE B MAIN LJ CONVERTER I8 is CONVERTER OUT B MODULATOR KE FRONT GOVERNOR L3 LUBRICATION B LOW CLUTCH TRIMMER REGULATOR EXHAUST OR SUMP REAR GOVERNOR FORWARD REGULATOR REGULATOR YALYE HT 740 HT750D AUTOMATIC TRANSMISSIONS FOURTH CLUTCH SECOND CLUTCH CORYERTER BY PASS YALYE FOURTH CLUTCH PRESSURE TAP ee FORWARD REGULATOR RN p aT od re 2 3 SHIFT MODULATOR a 3 4 SHIFT BE ADJUST SIGNAL YALYE 8 4 BH RING DRIVE 3 r vee thts GS THIRD CLUTCH 1 oRIFICE FIRST CLUTCH TRIMMER YALVE THIRD CLUTCH TRIMMER YALYE SECOM CLUTCH FOURTP CLUTCH TRIMMER VALVE TRIMMER VALVE SIGNAL TUBE F
10. 4 1 4 2 TOOLS AND EQUIPMENT a Improvised Tools and CUI INCI 4 1 eMe EIER 4 1 c Mechanic s Tools Shop EqUIpMEnt 4 1 4 8 IREPLACEMENT PARTS a Ordering Information 4 1 b Parts Normally 1 4 1 4 4 CAREFUL HANDLING 4 2 4 5 CLEANING INSPECTION a Dirt Causes Malfunction Cleaning Cleaning Bearings Keeping Bearings Clean Inspecting Cast Parts Machined Surfaces 4 11 Inspecting Bearings g Inspecting Bushings Thrust Washers 4 11 h Inspecting Sealrings SIS SIS NNI NIIT Inspecting Gears Inspecting Splined Parts Inspecting Threaded Parts Inspecting Snaprings Inspecting Springs Inspecting Clutch Plates Inspecting Swaged Inter ference fit Parts Inspecting Balls in Clutch HOUSINGS esc q Inspecting Sealing Surfaces ssssssnee h P Copyright 1983 General Motors Corp IV TABLE OF CONTENTS cont Paragraph Page 4 6 ASSEMBLY PROCEDURES d
11. 2 13 2 25 OIL PAN AND OIL FILTER a Description 2 13 b Function REAR ADAPTER HOUSING 2 14 REAR 2 14 2 28 TRANSFER GEAR HOUSING ADAPTER 2 14 2 29 TRANSFER GEAR HOUSING MANUAL DISCONNECT CLUTCH 2 31 HYDRAULIC SYSTEM a System Functions b System Schematics c Oil Filter Pump Circuit d Main Pressure Circuit e Converter Cooler Lubrication Circuit 2 15 f Selector Valve Forward Regulator Circuits 2 16 g Rear Governor Circuit 2 17 h Modulator Pressure eu m 2 17 i Trimmer Regulator Valve 2 17 J Trimmer 2 18 k Lockup Circuit Actuated by front governor HT 740D 747D HT 750 2 18 Copyright 1983 General Motors Corp TABLE OF CONTENTS cont Paragraph Page 2 32 2o0 0ooco0ocp gt P 2 34 IQP 2 39 Lockup Circuit Actuated by rear governor HT 740D HT 747D ERROR 2 18 Prorty 2 19 Clutch Circuits Drive Ranges
12. FIRST CLUTCH PISTON REAR PLANETARY CARRIER CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON EE CLUTCH APPLIED F TORQUE PATH 2963 Fig 2 16 First gear torque path 750DRD d First Gear Torque Path fig 2 16 Engine torque is transmitted through t h e torque converter as described in a above The forward and the low clutches are applied The low clutch anchors the low carrier against rotation The forward clutch application locks the turbine shaft and main shaft together so they rotate as a unit The rear planetary carrier sun gear is splined to the rotating main shaft and rotates at input speed This sun gear rotates the rear planetary carrier assembly pinions which in turn rotates the rear carrier ring gear Because vehicle inertia tends to restrain the output shaft and the rear carrier from rotation the rear carrier pinions rotate the rear ring gear This in turn rotates the low sun gear which is splined to the rear ring gear With the low carrier held stationary by the applied low clutch and the low sun gear rotating the low carrier assembly pinions the low ring gear must rotate Since the rear carrier and the low ring gear are splined to the output shaft a combination of rear and low planetary carrier output ratios are simultaneously introduced to the output shaft to form a speed reduction of 7 97 1 Copyright 1983 General Motors Corp 2 38 DESCRIPTION AN
13. Determine Plate Thickness 7 1 7 3 ESTABLISHING CLUTCH CLEARANCES SELECTING CENTER SUPPORT SNAPRING HT 740D HT 747D a First Clutch Clearance 7 1 b Selecting Center Support 14 7 2 c Second Clutch Clearance 7 4 Copyright 1983 General Motors Corp vii Paragraph TABLE OF CONTENTS cont 7 4 JESTABLISHING CLUTCH CLEARANCES SELECTING CENTER SUPPORT SNAPRING HT 750 CRD HT 754CRD HT 750 DRD HT 750DRD DB a b C Low and First Clutch Clearances 4 7 4 Selecting Center Support 7 6 Second Clutch Clearance 7 7 7 5 INSTALLING REAR COMPONENTS HT 740D 747D a b CIUC oresometetosseto tov mesas mE 7 7 Rear Cover Assembly 7 8 7 6 INSTALLING FIRST CLUTCH GEAR UNIT SECOND CLUTCH CENTER SUPPORT HT 750CRD HT 754CRD a b First Clutch Rear Planetary Ring Gear 7 8 Gear Unit Second Clutch Center Support 7 9 7 7 INSTALLING REAR COMPONENTS HT 750CRD HT 754CRD a b Adapter Housing Low Clutch Low Ring Gear 7 10 Low Planetary Rear Cover Assembly 22 2 7 8 INSTALLING GEAR UNIT SECOND CLUTCH CENTER SUPPORT HT 740D a b G
14. 7 22 CHECKING SHIFT POINTS 7 36 Paragraph Page POWER TAKEOFF COMPONENTS a Existing Installation b New Installation 7 37 7 38 Section 8 WEAR LIMITS AND SPRING DATA 8 1 SCOPE sssssssseeennes 8 1 8 2 WEAR LIMITS DATA Maximum Variations 8 1 b Cleaning Inspection 8 1 c Bearings Bearing JOU IS BOOS 8 1 HE INS Ss MM f Hook type Sealrings EE Eo 8 3 SPRING 8 1 FOLDOUT ILLUSTRATIONS back of Service Manual Cross section Views Model HT 740D HT 747D transmission Model HT 750CRD HT 754CRD transmission Model HT 750DRD transmission Model HT 750DRD DB transmission Schematic Views Model HT 740D HT 747D transmission hydraulic system Model HT 750CRD HT 754CRD transmission hydraulic system Model HT 750DRD transmission hydraulic system no lockup in first gear Model HT 750DRD transmission hydraulic system all range lockup Copyright 1983 General Motors Corp Ix FOLDOUT ILLUSTRATIONS cont Exploded Views Flex disc and flywheel assemblies B9 Transmission front cover remote mount Lockup clutch and torque converter Oil pump and converter housing for models without retarder or PTO Converter h
15. ut E MM L y TUL Pi Selig wy o EL h y el H ux wi dn o ROLLER 10 24218 2 Sz Fig 6 14 Installing stator free wheel roller STATOR CAM ROLLER SPRING 5950A Fig 6 15 Spring and roller in stator cam springs must be positioned as shown ir figure 6 15 5b Install ten freewheel rollers fig 6 14 6 Install the thrust bearing onto the freewheel roller race fig 6 16 7 Start the freewheel roller race into the stator until the thrust bearing is near the roller holder fig 6 16 Rotate the race clockwise to install it Copyright 1983 General Motors Corp 6 7 HT 740D HT 750D SERIES TRANSMISSIONS STATOR 52824 Fig 6 16 Installing freewheel roller race 8 Remove the roller holder by pulling on the thong attached to it Push the roller race inward rotating it clockwise until the thrust bearing seats 9 Rotate the freewheel roller race counterclockwise to lock in place Position the stator assembly with its roller race upward until ready for installation Cover or wrap the assembly to keep out dust and dirt 6 5 TORQUE CONVERTER PUMP ASSEMBLY a Disassembly Aj foldout 10 1 Remove sealring 31 from the front of converter pump 33 2 Flatten the corners of the lockstrips and remove twelve bolts from the converter pump 17 3 earlier models remove bolts 27 lockstrips 28 two piece bearing retainer 29
16. 18 Cover the opening to keep out dirt until the transfer housing is installed onto the transmission 6 29 TRANSFER GEAR HOUSING ADAPTER OUTPUT SHAFTS a Disassembly B foldout 19 1 If replacement is necessary remove needle bearing and bushing 34 or 42 from output shaft 35 or 41 2 Remove oil seal 11 B foldout 19 from transfer housing adapter assembly 9 NOTE This seal keeps the hydraulic fluid in the front section of the transmission separated from the oil in the dropbox BALL BEARING TRANSFER HOUSING TA ag 51124 Fig 6 99 Installing transfer drive gear 3 Place adapter assembly 9 piston side up on the work table 4 Using compressor J 24204 compress spring retainer 3 and remove snapring 2 5 Carefully release spring pressure and remove retainer 3 6 Remove thirty piston return springs 4 7 Remove sealrings 6 and 7 8 If parts replacement is necessary remove the following parts from the transfer housing adapter assembly governor support pin 13 dowel pins 14 and 15 and pipe plugs 12 low clutch piston 5 and NOTE Refer paragraph 6 2 b Assembly B foldout 19 1 If dowel pins 14 and 15 B foldout 19 were removed from adapter 10 install new pins The pins must extend 0 38 inch 9 65 mm above face of the adapter Copyright 1983 General Motors Corp 6 62 REBUILD OF SUBASSEMBLIES CAUTION The alignment of the governor support pin
17. 2 When hydraulic pressure is directed to the back side of piston 6 B 18 piston compresses clutch plates 1 foldout 18 and 2 together This locks the rotating internal plates to the stationary external plates preventing ring gear 4 from rotating 3 With the application of forward clutch in conjunction with first clutch a reaction within the planetary gearing will produce a forward rotation at the output shaft e Operation A foldout 18 HT 750DRD 1 Refer to c l above 2 When hydraulic pressure is directed to the back side of piston 6 A the piston compresses clutch plates 1 A and 2 together This locks the rotating internal plates to the stationary external plate preventing ring gear 3 from rotating 3 With the application of the forward or fourth clutch in conjunction with the first clutch refer to a 3 above a reaction within the planetary gearing will produce either forward or reverse rotation at the output shaft 2 15 LOW CLUTCH Bj foldout 18 A foldout 19 a Function Differs Among Models 1 Only the five speed transmissions include the low clutch Refer t figure 2 1 for its location Copyright 1983 General Motors Corp 2 8 DESCRIPTION AND OPERATION 2 The low clutch in the HT 750CRD and HT 754CRD has a dual function When engaged with the forward clutch it produces first gear When engaged with the fourth clutch it produces reverse gear 3 In the HT 750D
18. P i 14 Ha d E we fa TU A Tr L x E m I wee a t E UU i me Ls i f 4 T Als Fig 7 54 Installing control valve body 3 Install the lubrication check valve baffle and retain it with two 1 4 20 x 1 1 2inch bolts marked A fig 7 55 4 Install two 1 4 20 x 1 1 2 inch bolts B and two 1 4 inch washers through the oil transfer plate and into the transmission housing fig 7 55 Bolts A and B retain the oil transfer plate separator plate and control valve assembly to the transmission housing 7 57 5b Install thirteen 1 4 20 x 3 inch bolts C through the valve body assembly and into the housing 7 55 Remove two guide screws J 24315 3 and install the two remaining 1 4 20 x 3 in bolts Earlier models use seventeen 3 inch bolts two of which were replaced by two 1 2 bolts at the lower D positions in later models Install three 1 4 20 x 3 1 2 inch bolts D earlier models use only one at the top 1D position Install tile selector detent and retain it with a 1 4 20 x 2 1 2 inch bolt E 6 Install the lockup cutoff valve body assembly TENEAT 56 Retain it with eight 1 4 20 x 3 inch bolts Tighten all of the bolts to 8 12 Ib ft 11 16 Nem HT 740D 7500 AUTOMATIC TRANSMISSIONS TEN rrt F si i 2 100201100 AS vl CONTROL VALVE ET secos BODY ASSEMBLY ee
19. Torque Ib ft Nem A 4 5 5 7 B 67 80 91 108 C 600 800 813 1085 D 10 13 14 18 95 1 2 2 3 shift valve spring 96 1 2 2 3 shift valve stop 97 Spring adjusting ring 98 2 3 3 4 shift valve 99 2 3 3 4 modulator valve 100 2 3 3 4 shift valve spring 101 2 3 3 4 shift valve stop 102 Spring adjusting ring 103 Retainer pin 104 3 4 4 5 shift valve 105 3 4 4 5 modulator valve 106 3 4 4 5 shift valve spring 107 3 4 4 5 shift valve stop 108 Spring adjusting ring 109 Retainer pin 110 3 4 4 5 relay valve 111 Relay valve spring 112 3 4 4 5 relay valve stop 113 Retainer pin 114 Trimmer regulator valve 115 Trimmer regulator valve spring 116 Trimmer regulator valve stop 117 Retainer pin 7 S 118 Stop 119 Plug Torque Nem A 9 11 12 15 B 4 5 5 7 C 36 43 49 58 FOLDOUT 20 HT 740D HT 750D AUTOMATIC TRANSMISSIONS A Foldout 20 First and low piston rear cover output shaft and governor exploded view Copyright 1983 General Motors Corp B Foldout 20 Control valve assembly exploded view 1 Bolt 1 4 20 x 2 3 4 A 2 Low shift valve body assembly 3 Low shift valve body 4 Retainer pin HT 750CRD only 5 Retainer pin 6 Retainer pin 7 Relay valve 8 Relay valve spring 9 Relay valve stop 10 Low shift signal valve HT 750DRD only 11 Low shift signal valve HT 750CRD only 12 Low sh
20. aa i e n EN L d A Lou VETT T a ie NNNM T d gs x 3 ree EM M SIT DAE PLATE hi s uL d in 2736 n UN Se LOCK WASHER 14 tabs uri i I PLATE T E BOLT 110 20 X 112 LOCKWASHER Pro mmm up LEM di 53785 Fig 5 18 Control valve body bolt locations 9 Remove the control valve body assembly separator plate and transfer plate as a unit iS 5 191 Refer to or rebuild of the control valve body assembly Copyright 1983 General Motors Corp 5 8 SEPARATOR PLATE LUBRICATION VALVE 4 CONTROL VALVE ASSEMBLY DISASSEMBLY OF TRANSMISSION J 24315 3 53771 Fig 5 19 Removing control valve assembly 5 8 REMOVING TORQUE CONVERTER AND PTO COMPONENTS a Converter Stator Pump 1 Holding the stator assembly lock the stator and the freewheel roller race together by rotating the stator in a counterclockwise direction Refer to figure 5 8 Carefully lift the stator assembly from the turbine shaft Refer to paragraph 6 4 for rebuild of the stator assembly Remove snapring 25 Aj foldout 10 using tool J 26598 Hold the safety guards open fig 5 20 place the tool over the converter ground sleeve and snapring and position the jaws into the snapring gap Close the jaws by rotating the adjusting nut fig 5 21 SAFETY GUARDS 5
21. 4 Install twenty one 1 2 13 x 5 3 4 inch bolts and three 1 2 13 x 7 1 4 inch bolts and washers to retain the rear cover fig 7 21 Tighten the bolts to 67 80 Ib ft 90 108 N m 5 Install the governor assembly into the rear cover by rotating it counter clockwise fig 7 22 6 Install the governor cover gasket and cover and retain them with four 5 16 18 x 9 16 inch bolts Tighten the bolts to 10 13 Ib ft 14 17 Nem d Installation of Transfer Gear Housing Adapter Assembly B foldout 19 19 NOTE For ease of handling the drop box should not be installed until the main transmission IS assembled completely 1 Attach a 3 strand sling to rear of adapter 10 and install the adapter 2 Install two 1 2 13 x 7 3 4 inch bolts 22 and lockwashers 23 into opposite holes in the bolt circle 180 apart 3 Tighten bolts sufficiently to retain the adapter 4 Invert the transmission front upward 7 10 INSTALLING GEAR UNIT SECOND CLUTCH CENTER SUPPORT HT 750DRD DRD DB a Gear Unit Second Clutch 1 Remove the selective snapring that retains the center support fig 7 25 Remove the anchor bolt that retains the center support to the transmission housing 2 Install lifting bracket J 24195 onto center support and remove the support fig 7 24 3 Remove the second clutch snap ring Remove the second clutch plates Identify the pack and keep it intact 4 Remove the four 1 8 in
22. 41 e Overhaul stand fig 5 1 e Pins to retain low sun gear and hub assembly An improvised tool similar to that shown in ffig 4 6 is recommended This tool will prevent the accidental loss of one or more of the cotter pins in the transmission during disassembly or assembly fig 5 53 b Special Tools Special tools are illustrated in they are eerie nthe tables following the illustrations c Mechanic s Tools Shop Equipment The following tools in addition to the common tools ordinarily required should be available e Snapring pliers e Micrometer e 3 leg lifting sling of 1 2 ton 454 kg capacity with 900 angle attaching plates e Suitable hoist 1 2 ton 454 kg capacity e Container of volatile mineral spirits for cleaning parts CAUTION Caustic cleaning compounds will damage some transmission parts Use only mineral spirits A 100 inch pound 11 3 N m torque wrench A 100 foot pound 136 N m torque wrench A 1000 foot pound 1356 N m torque wrench A hot plate or heating equipment for heating bearings or other interference fit parts to aid assembly e Apress for disassembly and assembly of spring loaded clutches valves and interference fit parts Clean shop cloths do not use waste Boxes receptacles for parts Supply of wood blocks Oil soluble non fibrous grease petrolatum Nonhardening sealer Permatex No 2 or equivalent for plugs seals etc 4 3 REPLACE
23. 7 SECOND CLUTCH PESTON FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON Ey CLUTCH APPLIED F TORQUE PATH Fig 2 20 Fifth gear torque path HT 750DRD h Fifth Gear Operation fig _2 20 The forward and fourth clutches are applied Refer to paragraph 2 27g for detailed explanation of torque path flow Refer to paragraph 1 6 for fifth gear ratio Copyright 1983 General Motors Corp 2 42 DESCRIPTION AND OPERATION f LOCKUP CLUTCH TORQUE CONVERTER gt ROUTE k dto THIRD CLUTCH FIRST CLUTCH 4 HLGW CLUTCH Red FORWARD SECOND M oou b CLUTCH merui t eee n minut i airis lad 1 X EE m zn h s E gd LOW PISTON LOW PLANETARY CARRIER ere dnd phe nnn ERST CLUTCH PISTON Ds N ONE REAR PLANETARY CARRIER FORWARD CLUTCH PISTON MS CENTER PLANETARY CARRIER FOURTH CLUTCH PISTON oe ee NEN A FRONT PLANETARY CARRIER C MI TUN SECOND CLUTCH PISTON Emm CLUTCH APPLIED Ep TORQUE PATH 92963 Fig 2 21 Reverse gear torque path HT 750DRD i Reverse Gear Operation fig 2 21 The first and fourth clutches are applied Refer to paragraph 2 27h which explains the planetary action differing only in output shaft soeed reduction shown in Copyright 1983 General Motors Corp 2 43 HT 740D HT 750D AUTOMATIC TRANSMISSIONS REAR ADAPTER TRANSFER a i HOUSING GEAR HOUSING a n ee f n L
24. 7400 HT 747D Clutch Circuit Drive Ranges HT 750CRD HT 754 CRD 2 20 Clutch Circuit Drive Ranges HT 750DRD 2 21 Automatic Upshifts 2 22 Automatic Downshifts Downshift and Reverse Inhibiting csse TORQUE PATHS THROUGH TRANSMISSION HT 740D HT 747D Converter Operation Lockup Operation Neutral Operation First Gear Operation oecond Gear Operation Third Gear Operation Fourth Gear Operation Reverse Gear Operation TORQUE PATHS THROUGH TRANS MISSION HT 750CRD HT 754CRD Converter Operation Lockup Operation Neutral Operation First Gear Operation Second Gear Operation Third Gear Operation Fourth Gear Operation Fifth Gear Operation 225 Reverse Gear Operation 2 96 TORQUE PATHS THROUGH TRANSMISSION HT 750DRD Converter Operation Lockup Operation Neut
25. 54 Cover plate 55 Bolt 1 4 20 x 2 1 4 8 D 56 Signal tube C 57 Reducer Torque lb ft Nem A 67 80 91 108 B 4 5 5 7 C 15 20 20 27 D 9 11 12 15 E 13 16 18 22 F 17 20 23 27 FOLDOUT 17 HT 740D HT 750D AUTOMATIC TRANSMISSIONS A Foldout 17 Transmission housing oil filter and seven inch oil pan exploded view ap at wt 1 NN N M J GEET LPE T105 Copyright 1983 General Motors Corp B Foldout 17 Transmission housing oil filter and eight and one half inch oil pan exploded view A 1 External tanged clutch plate 7 0 0955 2 43 mm 0 1025 60 mm thk AR 0 1161 2 95 mmp0 1231 3 13 mm thk AR 2 Internal splined clutch plate 6 3 Rear planetary ring gear HT 750DRD 4 Rear planetary ring gear HT 740D amp HT 750CRD 1 Adapter housing gasket 2 Adapter housing and piston assembly 3 Self locking retainer ring 4 4 Spring retainer 5 Piston release spring 28 6 First clutch piston 7 Piston inner sealring 8 Piston outer sealring 9 Adapter housing assembly 10 Adapter housing 11 Dowel pin 3 8 x 3 4 12 Dowel pin 7 16 x 3 4 13 Orifice plug 14 Low clutch ring gear 15 Internal splined clutch plate 6 16 External tanged clutch plate 7 17 Ball bearing 18 Low planetary carrier assembly 19 Low carrier 20 Pinion pin 21 Bronze thrust washer 8 22 Needle roller bea
26. 6 33 b Assembly 6 34 6 19 CENTER SUPPORT ASSEMBLY a Disassembly 6 36 b Assembly 6 37 6 20 GEAR UNIT AND MAIN SHAFT ASSEMBLY HT 740D 747D a Disassembly 6 38 b Replacing Sun Gear Shaft scu q 6 39 c Assembly 6 42 6 21 GEAR UNIT AND MAINSHAFT ASSEMBLY HT 750DRD HT 750DRD DB a Disassembly 6 43 b Assembly 6 43 6 22 GEAR UNIT AND MAIN SHAFT ASSEMBLY HT 750CRD HT 754CRD a Disassembly 6 45 b Assembly 6 46 6 23 PLANETARY CARRIER ASSEMBLIES a Assembly Inspection 6 46 b Removal Installation of Pinion Components c Replacing Bushing in Front Planetary Carrier Assemblies 6 49 6 24 LOW SUN GEAR AND HUB HT 750DRD HT 750DRD DB 6 50 6 25 ADAPTER HOUSING ASSEMBLY HT 750 a Disassembly 6 50 b Assembly 6 50 REAR COVER ASSEMBLY a Disassembly b
27. Green stripe Solid yellow white stripe oolid blue orange stripe oolid blue oolid blue green stripe Solid white Spring Free Copyright 1983 General Motors Corp 8 14 No Wire dia OD Length Length Under Load Coils 1n mm 1n mm 1n mm 1n mm 16 N 12 0 054 0 640 2 44 1 15 7 45 to 8 05 1 37 16 3 61 9 29 2 33 14 to 35 81 12 0 054 0 640 2 53 1 15 7 95 to 8 55 1 37 16 3 64 3 29 2 35 4 to 38 0 12 0 054 0 640 2 57 1 15 8 20 to 8 80 1 37 16 3 65 3 29 2 36 5 to 39 1 12 0 052 0 640 2 65 1 15 8 65 to 9 35 1 32 16 3 67 3 29 2 38 47 to 41 59 12 0 052 0 640 2 69 1 15 8 90 to 9 60 1 32 16 3 68 3 29 2 39 59 to 42 70 12 0 054 0 640 2 78 1 15 9 4 to 10 1 1 37 16 3 70 6 29 2 41 8 to 44 9 12 0 054 0 640 2 86 1 15 9 90 to 10 60 1 37 16 3 72 6 29 2 44 0 to 47 2 12 0 054 0 640 2 94 1 15 10 4 to 11 2 1 37 16 3 74 7 29 2 46 0 to 49 6 14 0 062 0 640 2 37 1 15 11 0 to 11 5 1 57 16 3 60 2 29 2 48 9 to 51 2 14 0 062 0 640 2 40 1 15 11 3 to 11 8 1 57 16 3 60 9 29 2 50 0 to 52 3 14 0 062 0 640 2 45 1 15 11 8 to 12 3 1 57 16 3 62 2 29 2 52 3 to 54 5 14 0 062 0 640 2 48 1 15 12 0 to 12 5 1 57 16 3 62 9 29 2 53 4 to 55 6 14 0 062 0 640 2 54 1 15 12 5 to 13 0 1 57 16 3 64 5 29 2 55 6 to 57 8 12 0 054 0 640 1 82 1 15 3 75 to 4 25 1 37 16 3 46 2 29 2 16 7 to 18 9 12 0 054 0 640 2 94 1 15 10 35 to 11 15 1 3
28. 1 99 50 4 1 74 44 3 2 43 61 7 2 53 64 3 2 57 65 3 2 67 67 8 2 75 69 9 2 85 72 4 2 98 75 7 2 62 66 6 2 55 64 8 2 82 71 6 2 23 56 6 2 36 59 9 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 Length Under Load 1n mm Ib N 10 75 to 11 25 47 8 to 50 0 8 22 to 8 72 36 6 to 38 8 5 97 to 6 15 26 6 to 27 4 11 45 to 11 95 50 9 to 53 2 12 25 to 12 75 54 5 to 56 7 12 74 to 13 26 56 7 to 59 0 13 45 to 14 05 59 8 to 62 5 9 25 to 9 95 41 1 to 44 3 9 85 to 10 55 43 8 to 46 9 10 60 to 11 40 47 2 to 50 7 8 50 to 9 10 37 8 to 40 5 8 10 to 8 70 36 0 to 38 7 9 65 to 10 35 42 9 to 46 0 6 20 to 6 80 27 6 to 30 3 6 95 to 7 55 30 9 to 33 6 Fold out 20 B Ref 91 Spring 1 2 shift valve Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Part No 6884938 6884940 6884941 6884943 6884944 6884946 6884947 6884949 6884950 6884951 6884953 6884954 6884955 6885065 23012949 23012937 Table 8 2 SPRING DATA cont Color Code Solid white red stripe Solid yellow orange stripe Red stripe Solid white orange stripe oolid blue red stripe Solid yellow white stripe Solid white green stripe Blue stripe Solid green white stripe Orange stripe
29. 30 5 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 10 27 9 1 15 29 2 1 15 29 2 1 15 29 2 1 15 L29 2 Length Under Load in mm Ib N 11 8 to 12 3 52 3 to 54 5 12 95 to 13 55 57 60 to 60 27 10 35 to 11 15 14 0 to 15 1 10 6 to 11 4 14 4 to 15 5 10 75 to 11 25 14 6 to 15 3 9 15 to 9 85 12 4 to 13 4 16 20 to 19 80 72 0 to 88 0 8 6 to 9 1 38 3 to 40 5 9 35 to 9 85 41 6 to 43 8 7 85 to 8 35 34 9 to 37 1 7 18 to 7 68 31 9 to 34 2 7 20 to 8 80 32 0 to 39 1 10 0 to 10 5 44 3 to 46 5 7 9 to 8 6 35 4 to 38 0 8 65 to 9 35 38 5 to 41 6 8 9 to 9 6 39 6 to 42 7 Fold out Ref 102 Spring 3 4 shift valve Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Table 8 2 SPRING DATA cont Part No 6835310 6837454 6838356 6838357 6880991 6880992 6880993 6881060 6881061 6883665 6884938 6884941 6884943 6884945 6884946 688494 7 Color Code oolid green oolid yellow oolid blue yellow stripe Solid red oolid blue red stripe Solid white red stripe Solid green white stripe Solid yellow orange stripe oolid blue orange stripe Solid white green stripe Solid white red stripe Hed stripe Solid white orange stripe Solid green white stripe Solid yellow white stripe Solid white green stripe No Coils 13 10 8 12 8 18 Wire dia in mm 0 059 1 50 0 056 1 42 0 062 1
30. Detailed instructions are provided for disassembly and rebuild Spring data is shown in Troubleshooting and part inspection are shown in Sections 3 and 4 b Illustrations 1 Ihe text is illustrated with photographs line drawings and cross section views The overhaul procedures are illustrated mainly by photographs Line drawings are used to supplement detailed assembly procedures cross sections show the torque paths and relationship of assembled parts Cross sections color coded schematics of the hydraulic system and all exploded views are on foldout pages at the back of the manual 2 Certain illustrations will not always show the model being serviced However the illustration will show the correct procedure c Maintenance Information Each task outlined in this Service Manual has been successfully accomplished by service organizations and individuals It is not expected that every service organization or individual will possess the required special tooling training or experience to perform all the tasks outlined However any task outlined herein may be performed if the following conditions are met 1 The organization or individual has the required knowledge of the task through e Formal instruction in a DDA or Distributor training facility e On the job instruction by a or Distributor representative e Experience in performing the task 2 The work environment is suitable to prevent contamination o r damage to tr
31. Self locking bolt 3 8 24 x 1 1 4 30 B 45 Washer 30 Torque Ib ft Nm A 33 40 45 54 B 41 49 56 66 FOLDOUT 10 1 Oil pump assembly 2 Oil seal 3 Oil pump body 4 Plug 3 4 3 Non retarder Automotive hag 5 Oil pump drive gear 6 Driven gear shaft 7 Driven gear assembly 8 Driven gear 9 Roller bearing 10 Pump cover 11 Flat Head machine screw 1 4 20 x 5 8 A 12 Sealring 13 Bolt 3 8 16 x 3 4 2 3 14 Converter access cover 15 Converter access cover gasket 16 Converter housing 17 Converter housing gasket 18 Pipe plug 1 8 4 C 19 Bolt 7 16 14 x 1 1 2 22 D 20 Lockwasher 7 16 22 21 Lockwasher 1 2 7 22 Bolt 1 2 13x 2 7 E 23 Flat washer 2 24 Fillister ead machine screw 2 F Torque Ib ft N m A 9 11 12 15 B 26 32 35 43 C 4 5 5 7 D 42 50 57 68 E 67 80 91 108 F 10 32 3 5 e Assemblies not equipped with hydraulic retarder require only one of each those with retarder require two A 56 Bolt 1 2 13 x 6 1 4 3 with retarder B B 1 Bolt 3 8 16x 1 1 2 g A 5 Lock washer 1 2 with retarder 1 Bolt 3 8 16 x 3 4 2 A FOLDOUT 11 2 Converter ground sleeve 58 Bolt 1 2 13 x 6 1 2 with retarder B 2 Converter housing access cover 3 Bolt 1 2 13 x 2 1 4 2 Nonretarder models B 59 Lubrication valve spring with retarder 3 Converter housing access cover gasket 4 Plain washer 1 2 2 Non retarder models 60 Lubrication v
32. lockup shift valve 8 and converter bypass valve 14 2 10 DESIGNATION OF CLUTCHES PLANETARY GEAR SETS a Necessary for Clarity of Description 1 In this section and those following uniform designations for clutches and planetary gear sets are used for all models in the HT 700D series In the first edition of the manual which covered only the HT 740D model transmission clutches were designated to match the transmissions forward gear selections first second third fourth and forward With the introduction of new models with an additional clutch and g e a r set and the changes in functions of each clutch among models such designation is no longer practical Also a similar situation exists for the planetary gear sets The first edition of the manual covered only the HT 740D model transmission which included only three gear sets These were designated front center and rear for their relation to the position of each other and to transmission front and rear The five speed models which have been added include another gear set Thus it was necessary to assign uniform designations to each planetary gear set applicable to all models 2 Accordingly to avoid confusion in the designation of and reference to clutches and planetary gear sets the methods outlined in b and c following were Copyright 1983 General Motors Corp 2 4 DESCRIPTION AND OPERATION b Clutch Designations 1 Each clutch in the same physical
33. 1 Shifting from neutral The engine should be at idle speed when any shift from neutral to a drive range is made 2 Drive D This range is the most commonly used forward range It includes all forward gears on the HT 740D HT 747D HT 750CRD HT 754CRD n d the upper four ranges on the HT 50DRD drive in this range simply depress the accelerator The transmission will start in first second on HT 750DRD and automatically upshift at the proper speeds through all gears Downshifts also will occur automatically in relation to speed and throttle position 3 Drive 4 4 HT 750 only In this range the transmission will start in first second on HT 50DRD and automatically upshift at the proper speeds to the fourth gear 4 Drive 3 3 In this range the transmission will start in first second on HT 750DRD automatically upshift at the proper speeds to third gear 5 Drive 2 2 In this range the transmission will start in first second on HT 750DRD automatically upshift at the proper speeds to second gear The HT 750DRD will remain in second gear 6 Drive 1 1 In this range the transmission will start in first gear No automatic upshift will occur unless governed speed is exceeded d Reverse To move the vehicle backward idle the engine and shift the selector to the reverse position Depressing the accelerator will then cause the vehicle to back up e Range Selection Drive D r
34. 29 2 59 8 to 62 5 12 0 054 0 640 2 75 1 15 9 25 to 9 95 1 37 16 3 69 9 29 2 41 1 to 44 3 12 0 054 0 640 2 85 1 15 9 85 to 10 55 1 37 16 3 72 4 29 2 43 8 to 46 9 12 0 054 0 640 2 98 1 15 10 60 to 11 40 1 37 16 3 75 7 29 2 47 2 to 50 7 12 0 054 0 640 2 62 1 15 8 50 to 9 10 1 37 16 3 66 6 29 2 37 8 to 40 5 12 0 054 0 640 2 93 1 15 10 50 to 10 95 1 37 16 3 74 4 29 2 45 6 to 48 7 12 0 054 0 640 2 82 1 15 9 65 to 10 35 1 37 16 3 71 6 29 2 42 9 to 46 0 12 0 054 0 640 2 57 1 15 8 2 to 8 8 1 37 16 3 65 3 29 2 36 5 to 39 1 12 0 054 0 640 2 69 1 15 8 9 to 9 6 1 37 16 3 68 3 29 2 39 6 to 42 7 12 0 054 0 640 273 1 15 9 2 to 9 9 1 37 16 3 69 3 29 2 40 7 to 43 8 12 0 054 0 640 2 78 1 15 9 4 to 10 1 1 37 16 3 70 6 29 2 41 8 to 44 9 12 0 054 0 640 2 86 1 15 9 9 to 10 6 1 37 16 3 72 6 29 2 44 0 to 47 2 12 0 054 0 640 2 90 1 15 10 2 to 10 9 1 37 16 3 73 7 29 2 45 4 to 48 3 12 0 054 0 640 2 94 1 15 10 35 to 11 15 1 37 16 3 74 7 29 2 46 0 to 49 6 14 0 062 0 640 2 40 1 15 11 3 to 11 8 1 57 16 3 60 9 29 2 50 0 to 52 3 14 0 062 0 640 2 37 1 15 11 0 to 11 5 1 57 16 3 60 2 29 2 48 9 to 51 2 8 16 Copyright 1983 General Motors Corp Fold out Ref 20 Bl 96 102 Spring 2 3 shift valve 3 4 shift valve Mean dimension shown Part No 6884953 6884956 23012949 23012951 23012954 23013271
35. 73 7 2 98 75 7 2 51 63 8 2 57 65 3 2 69 68 3 2 73 69 3 2 53 64 3 2 18 55 4 1 52 38 6 1 78 45 2 1 87 47 5 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 20 30 4 1 10 27 9 0 78 17 8 1 14 29 0 Length Under Load in mm Ib N 10 2 to 10 9 45 2 to 48 3 10 4 to 11 2 46 0 to 49 6 11 0 to 11 5 48 9 to 51 2 11 75 to 12 25 52 27 to 54 49 12 0 to 12 5 53 3 to 55 6 10 15 to 10 85 45 2 to 48 3 10 6 to 11 4 14 4 to 15 5 10 75 to 11 25 14 6 to 15 3 8 2 to 8 8 11 1 to 11 9 8 9 to 9 6 12 1 to 13 0 9 15 to 9 85 12 4 to 13 4 7 95 to 8 55 10 8 to 11 6 16 2 to 19 8 72 1 to 88 1 7 2 to 8 8 32 0 to 39 1 3 80 to 4 20 16 9 to 18 7 4 25 to 4 75 18 9 to 21 1 HT 740D HT 750D AUTOMATIC TRANSMISSION Table 8 2 SPRING DATA cont Spring Free Mean dimension shown Copyright 1983 General Motors Corp 8 20 Fold Color No Wire dia OD Length Length Under Load out Ref Spring Part No Code Coils in mm mm mm mm Ib 111 Trimmer regulator 6880186 Solid yellow 12 0 041 0 464 1 37 0 89 2 43 to 2 69 valve blue stripe 1 04 11 8 34 8 22 6 10 8 to 11 9 6880246 Solid blue 13 0 041 0 464 1 81 0 89 4 25 to 4 75 1 04 11 8 46 0 22 6 18 9 to 21 1 21 8 Low shift relay 6768544 Solid yello
36. ACTIVE MODULATOR MAIN LOCKUP FRONT GOVERNOR 17544 Fig 3 7 Transmission check points with retarder Copyright 1983 General Motors Corp 3 19 HT 740D HT 750D AUTOMATIC TRANSMISSIONS APRIL 1975 PRIOR TO S N 8250 LUBE NOT ACTIVE 4 E EFFECTIVE JANUARY 1976 ZD AFTER S N 11249 MOD ULATOR MAIN LOCKUP NOT p FRONT ACTIVE GOVERNOR LUBE MAIN 0 i L APRIL 1975 AFTER S N 8249 FRONT LOCKUP GOVERNOR FRONT LOCKUP GOVERNOR Fig 3 8 Transmission check points with retarder and engine driven PTO Copyright 1983 General Motors Corp 3 20 PREVENTIVE MAINTENANCE NEUTRAL START REAR GOVERNOR SWITCH LOCATION PRESSURE REVERSE SIGNAL FOURTH CLUTCH HT SWITCH LOCATION FIFTH CLUTCH CLT amp CLBT REAR GOVERNOR GOVERNOR FEED PRESSURE Fig 3 9 Transmission check points all models Copyright 1983 General Motors Corp 3 21 A 1 2 7400 7500 AUTOMATIC TRANSMISSIONS Table 3 1 TROUBLESHOOTING CHART Cause AUTOMATIC SHIFTS OCCUR AT TOO HIGH SPEED Governor valve stuck Shift signal valve spring adjust ment too tight 3 4 B O OR ONS pw Im Im Valves sticking Shift points not properly adjusted AUTOMATIC SHIFTS OCCUR AT TOO LOW SPEED Governor valve stuck Governor spring weak Shift signal valve spring adjust ment too loose Modulator valve stuck Shift points not properly adjusted LOW
37. All the metalic p a r t s of the transmission except bearings and frictionfaced clutch plates should be cleaned thoroughly with volatile mineral spirits or by the steam cleaning method Do not use caustic soda solution for steam cleaning Use only mineral spirits to clean friction faced clutch plates 2 Parts should be dried with compressed air Steam cleaned parts should be oiled immediately after drying 3 Clean oil passages by working a piece of soft wire back and forth through the passages and flushing with mineral spirits Dry the passages with compressed air Copyright 1983 General Motors Corp 4 2 GENERAL OVERHAUL INFORMATION T 101 Fig 4 2 Special tools 1 through 21 Copyright 1983 General Motors Corp 4 3 HT 740D HT 750D AUTOMATIC TRANSMISSIONS T 102 Fig 4 3 Special tools 22 through 50 Copyright 1983 General Motors Corp 4 4 GENERAL OVERHAUL INFORMATION Fig 4 4 Special tools 51 through 87 Copyright 1983 General Motors Corp 4 5 HT 740D HT 750D AUTOMATIC TRANSMISSIONS Fig 4 5 Special tools 88 through 116 Copyright 1983 General Motors Corp 4 6 Tool No J 1126 J 3387 2 J 6125 1 J 6889 1 J 8092 J 23544 5 J 24171 J 24171 1 J 24171 2 J 24171 4 J 24192 J 24193 J 24194 J 24195 J 24196 J 24197 J 24198 J 24200 J 24200 1 J 24200 2 J 24201 J 24202 IA J 24202 4 S Te pm m o e e t afe ge FS a a s
38. CO I JO Ap CO Co T Item 106 107 19 109 24 25 29 30 31 GENERAL OVERHAUL INFORMATION SPECIAL TOOLS Description Converter housing guide screws 1 2 13 part of J 24315 Oil pan guide screw 5 16 18 X 3 2 part of J 24315 Slide hammer used with J 24205 2 and J 24412 2 Pitot tube guide screw 10 32 X 6 2 part of J 24315 Driver handle used with J 24371 J 24197 J 24769 J 24368 Puller body Puller body screw Forcing screw Idler gear spindle puller set Idler gear spindle puller screw 1 2 20 thread Idler gear spindle remover Idler gear spindle puller screw 1 1 4 12 thread oeal and dust shield remover Jaw attachment Rod assembly Slide hammer Clutch pack clearance gage forward fourth Clutch pack clearance gage third Clutch pack clearance gage first second low Center support lifting bracket Main shaft lifting bracket Front support needle bearing installer Oil pump and dust shield installer used with J 24202 4 Collector ring installer and staking set Staking tool Collector ring installer oun gear shaft bushing installer Output shaft seal installer used with J 24202 4 Driver handle used with items J 24198 J 24202 1 J 24447 Copyright 1983 General Motors Corp 4 7 Ref Paragraph 7 12a 4 6 28a 5 6 28a 5 6 28a 5 3 16a 4 6 26a 1 2 3 16a d 6 26a 1 2 3 16a 4 mms 6 26b 13 HT 740D HT 750D A
39. CONVERTER HOUSING BOLT 3 8 16 X 1 1 2 8 M D Meme CONVERTER Ar GROUND Fig 6 33 Converter ground sleeve installed housing with 8 bolt covers 10 Remove lubrication valve components pin valve and spring if replacement is necessary fig 6 34 11 Remove plugs 13 14 15 and 16 A foldout 11 if cleaning or replacement is necessary Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS CONVERTER ROUSING F CONVERTER GROUND SLEEVE Fig 6 34 Converter housing with ground sleeve removed housing with 8 bolt covers 12 Remove dowel pins 11 12 if replacement is necessary NOTE Refer to above b Assembly 1 If dowel pins 11 or 12 A foldout 11 were removed install new pins Press them into the housing until 0 440 inch 11 17 mm is projecting 2 If plugs 14 13 or 16 were removed install them with sealant Tighten plug 14 to 70 90 Ib ft 95 122 N m plug 13 to 110 130 Ib ft 149 176 Nem plug 16 to 16 20 Ib ft 22 27 Nem 3 lf plug 15 was removed coat the circumference of a new plug with nonhardening sealer and install it flat side first Press or drive it 0 020 to 0 060 inch 0 5 to 1 5 mm below the surface surrounding the bore 4 If spindle 17 A foldout 11 was removed install a new spindle The assembly procedure for spindle 35 A foldout 11 is explained ACTA 112 10 Spindle 17 is symmetrical and may be
40. Fourth gear Third and forward Fifth gear Fourth and forward Reverse gear Low and fourth 2 Each of the six clutches has its own circuit Each clutch except the forward clutch is connected to a relay valve and a trimmer valve The forward clutch is connected directly to the selector valve and does not require connection to a trimmer valve because the vehicle is not moving 3 The low clutch circuit connects the clutch to the 1 2 relay valve and to the low trimmer valve In neutral the 1 2 shift valve feeds main pressure to the top of the 1 2 relay valve As long as main pressure is at the top of the 1 2 relay valve the valve cannot move Until the 1 2 shift valve is charged by governor pressure main pressure will continue to hold the 1 2 relay valve down Therefore hydraulic fluid is directed to only one clutch Since two clutches are required to move the vehicle and since governor pressure is negligible until the vehicle is moving neutral is maintained refer tq fig 2 8 4 The low clutch in addition to being applied during neutral operation is also applied in first and reverse gears Shifting the selector valve from neutral to drive 5 D5 position or any other forward drive range D4 D3 D2 D1 charges the forward clutch circuit and applies the forward clutch The low clutch remains charged Hydraulic fluid is directed from the selector valve to the forward clutch lt is also directed through the priority valve to the 2
41. Make pressure tests in conjunction with troubleshooting procedures outlined in paragraphs 3 17 thru 3 21 Refer to paragraph 1 6 for pressures 3 18 TROUBLESHOOTING BEFORE REMOVAL OR OPERATION a Visual Inspection Do not operate the vehicle prior to completing the procedures described in this paragraph Inspect for oil leakage Visually inspect all splitlines plugs all hose and tube connections at the transmission and cooler Oil leakage at splitlines may be caused by loose mounting bolts or defective gaskets Tighten all bolts plugs and connections where leakage is found Check to ensure that the modulator control cable and linkage are free b System Knowledge The engine transmission must be regarded as a single package during troubleshooting A thorough study of the description and operation of the components and hydraulic system will be helpful in determining the cause of trouble 3 19 TROUBLESHOOTING DURING OPERATION a Determine Trouble Cause If inspection para 3 18 above does not reveal the cause of trouble and the vehicle is operational further troubleshooting is necessary Do not remove the transmission from the vehicle until the causes of trouble are checked against the troubleshooting chart below b Properly Tuned Engine To make a thorough test of the vehicle mounted transmission be sure that the engine is properly tuned and that the oil level in the transmission is correct R
42. Note 7 18b 1 4 J 24315 3 4 5 105 Valve body guide screw 1 4 20 x 5 2 5 7b 2 5 7 16a 1 J 24365 4 4 54 Flywheel lifting bracket J 24368 4 3 49 Rear planetary carrier bushing installer J 24369 4 3 35 Orifice plug output shaft installer NR Not referenced in paragraph Copyright 1983 General Motors Corp 4 8 Tool No J 24371 J 24412 2 J 24420 1 J 24447 J 24453 J 24534 J 24769 J 25000 1 J 25000 227 J 25007 J 25007 2 J 25007 3 J 25007 4 J 25562 J 25587 01 J 26282 J 26401 J 26598 A J 26899 J 26899 1 J 26889 2 J 26901 A J 26997 A J 26997 1 J 26997 2 J 28489 J 28489 1 J 28489 2 J 28489 3 J 28489 4 J 28489 6 J 28525 J 28525 1 J 28525 2 J 28557 J 28646 A J 28684 J 29121 J 29121 1 J 29121 2 J 29121 3 J 29121 4 NR Not referenced in paragraph F E elelelele APA IATA TA abf Oy AIAI 4 4 Nis AA GENERAL OVERHAUL INFORMATION SPECIAL TOOLS Description Ref Paragraph Low sun gear bushing installer 6 24 Valve pin remover used with J 6125 1 Universal puller body used with J 24534 Rear bearing installer used with J 24202 4 Retaining ring installer Rear bearing puller legs 2 used with J 24420 Output shaft bushing installer HT 750DRD used with J 8092 Valve body and governor test stand Valve body test stand adapter Torque converter pump bearing puller Leg and nut assembly 4 Puller body Sleeve Output shaf
43. against both the inner and outer bearing race grooves Install puller head tool J 25007 3 onto the legs tightening the nuts evenly 11 Install center screw J 8646 2 and tighten it by hand until it is centered on sleeve J 25007 4 Hold the pump assembly and tighten the center screw until the pump assembly will lift off the ground sleeve Refer for rebuild of the pump assembly NOTE The inner race of the split race bearing is a press fit onto the ground sleeve o o models after S N 2081 contained a split outer race converter pump hub bearing 6752471 Remove as follows Select two 3 8 24 X 1 1 4 inch bearing retainer bolts 1800 apart ig 5 21 Bend the lockstrips clear of the bolts Remove the two bolts 13 Using figure 5 24 jas a guide install sleeve 25007 4 over the converter ground sleeve Copyright 1983 General Motors Corp 5 10 DISASSEMBLY OF TRANSMISSION J 8433 1 PULLER BODY o 4 22214 4 GROUND FORCING SCREW SLEEVE J 26901 A PULLER BOLT 2 4 24007 A A EENS 54537 Fig 5 24 Removing torque converter pump 16 Install the two 3 8 24 puller body studs into the two bearing retainer bolt holes Tighten each stud finger tight 17 Place puller body J 8433 1 withforcin g screw J 22214 4 onto sleeve J 25007 4 Insert studs J 26901 A through the puller b o d y as shown n ligure 24 Tighten the forcing screw and two stud nuts finger
44. b New Installation 1 Contact Detroit Diesel Allison Division for approval of planned installation or for recommen dations 2 Speeds type of duty power requirements and other factors must be considered when adding a PTO to a transmission lf the job requirements of the PTO cannot be fully met by the transmission the installation will not be satisfactory Also the transmission could be damaged 3 Follow all of the recommendations ina above 4 If a lubrication source is required the return line from cooler to transmission may be tapped Provide a 0 060 0 110 inch 1 52 2 79 mm restriction in the lubrication circuit for engine driven PTO or 0 032 inch 0 81 mm restriction for converter driven PTO This restriction is usually provided in the PTO Copyright 1983 General Motors Corp 7 37 7 38 Section 8 WEAR LIMITS AND SPRING DATA 8 1 SCOPE This section tabulates wear limits and spring data 8 2 WEAR LIMITS DATA a Maximum Variations Wear limits information in this section shows the maximum wear at which components are expected to function satisfactorily Table 8 1 lists the wear limits data and is referenced to the exploded views foldouts 9 through 23 in the back of this manual b Cleaning Inspection Parts must be clean to permit effective inspection for wear or damage Refer to Section 4 c Bearings Bearing Journals Bores The application of bearings to any product is based on the recom
45. in the same manner Each trimmer includes from top to bottom an orificed trimmer valve trimmer valve plug trimmer spring and stop pin 3 When any clutch except forward is applied apply pressure is sent also to the upper end of the trimmer valve Initially the valve and plug are forced downward against the trimmer spring until oil escapes to exhaust This escape of oil as long as it continues reduces clutch apply pressure However oil flows through an orifice in the trimmer valve to the cavity between the trimmer valve and plug Pressure in this cavity forces the plug farther downward to the stop The plug stops but flow through the orifice in the trimmer valve continues The pressure below the timmer valve because it is acting upon a greater diameter than at the upper end pushes the trimmer valve to the top of the valve bore This throttles then stops the escape of oil to exhaust When escape of oil is stopped clutch apply pressure is at maximum value The plug remains downward against the stop until the clutch is released 4 When the clutch is released the trimmer spring pushes the trimmer components to the top of the bore In this position the trimmer is reset and ready to repeat the trimming action when its clutch is again engaged 5 In current models a trimmer boost accumulator valve is connected to the trimmer regulator pressure circuit The accumulator will absorb surges in the trimmer regulator pressure
46. linkage and cables Check the transmission oil level at the intervals specified in the vehicle or transmission operator s manual 3 3 DIPSTICK CALIBRATION a dipstick must be properly calibrated at initial installation of the transmission If any doubt exists as to the calibration of the dipsticks refer to b through e below b Six inch deep oil pan transmission oil dipstick should be calibrated for the 6 inch deep oil pan as shown in c Seven and eight and one half inch deep oil pan The transmission oil dipstick should be calibrated for the 7 or 8 1 2 inch deep oil pan as shown fig 3 2 d Earlier model dipsticks were calibrated with Full and Add marks Such dipsticks may be recalibrated as shown in fig 3 3 e Dropbox models The dropbox fill pipe and oil level indicator should have the Full mark 2 inches 50 mm below a horizontal line through the center of the output drive TOP OF OIL PAN 1 50 38 1 mm 3 75 95 25 HOT RUN BAND 160 200 F 71 93 CI COLD RUN BAND 60 120 F 16 49 CI 12856 Fig 3 1 Oil levels 6 inch deep pan DIFFERENCE BETWEEN FULL AND ADD LEVELS 2 50 IN 152 0 5 QUARTS 63 5 mm 1 9 LITRES HOT RUN BAND 160 200 F 71 93 C 3 50 IN 88 9 mm 4 75 120 65 mm COLD RUN BANO 60 120 F 146 49 15590A Fig 3 2 Oil levels 7 and 8 1 2 inch deep pan TRANSMISSION TO OIL PAN SPLITLINE TOP OF
47. m X X X X X X au lc X X X zi X X X FL of SO GIA X X X X X X auis BD X X X X X 745 GAD RET io ox X X X X H1 790DhbD DB di E X Torque multiplication ratio at stall 3 04 1 2 21 1 1 83 1 2 70 1 2 56 1 2 09 1 Sore Ea Automatic in selected ranges i 1a Dri Planetary straight cut spur constant mesh CONC ETE Oil cooled hydraulically actuated spring released self compensating for wear Integral Copyright 1983 General Motors Corp 1 9 HT 740D HT 750D AUTOMATIC TRANSMISSIONS SPECIFICATIONS AND DATA CHART cont Oil systems Oll POLIT e Engine driven positive displacement Oil pump scavenge scende ME SE cR UMANE Engine driven positive displacement spur gear type NIU ees External customer supplied Suction screen in sump Oil Pan Depth Oil capacity 6 or 7 inch 8 1 2 inch 4 5 inch Initial fill as received from 8 25 U S gal 9 5 U S gal 8 50 5 gal factory or refill transmis 31 liters 36 liters 32 2 liters sion only SINT m Above 30 F 34 C hydraulic transmis sion fluid type Dexron or Dexron Il Below 30 F 34 hydraulic transmission fluid
48. measurement as outlined in 5 below An alternate method is by stack dimension computation outlined in paragraph 6 33 If the stack method is used disregard 2 through 5 below 2 Place the transmission housing in a vertical position rear end upward 7 1 3 Beginning with an external tanged clutch plate alternately install seven external tanged and six internal splined first clutch plates fig 7 1 4 Install the rear cover assembly as assembled in and gasket onto the rear of the transmission housing and secure it with six 1 2 13 bolts and flatwashers evenly spaced Refer to Tighten the bolts to approximately 30 Ib ft 41 Mm Copyright 1983 General Motors Corp 7 1 HT 740D HT 750D AUTOMATIC TRANSMIISSIONS EN COM LU TRANSMISSION De P mue TM WO 81975 Fig 7 1 Installing first clutch external tanged plate v E Fig 7 3 Installing second clutch external tanged plate niet i y MR EE 1 LE 51976 Fig 7 2 Checking first clutch clearance HT 740D 747D 5 Invert the transmission housing front ned upward Using clearance gage J 24194 check the clearance between the clutch plates fig 7 2 The Fig 7 4 Installing second clutch snapring prescribed clearance is 0 095 to 0 145 Inch 2 41 to 3 68 E mm Any dimension within 0 095 to 0 145 inch is 1 Beginning with an external tanged plate satisfactory However the closer the clear
49. must be applied to produce output shaft rotation in either forward or reverse Copyright 1983 General Motors Corp 2 30 TORQUE CONVERTER FORWARD zi CLUTCH T a bo ZOET pi M PHAT FORWARD CLUTCH PISTON FOURTH CLUTCH F ISTON THIRD CLUTCH PISTON FOURTH CLUTCH THIRD CLUTCH DESCRIPTION AND OPERATION FIRST CLUTCH r LOW CLUTCH OUTPUT SHAFT were eer a E WHEL ON REAR PLANETARY CARRIER C7 CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON WES IL CLUTCH APPLIED TORQUE PATH 3 52962 Fig 2 9 First gear torque path HT 750CRD 754CRD d First Gear Operation fig 2 9 Engine t o r que is transmitted through the torque converter as described in a above The forward and low clutches are applied The low clutch application anchors the rear planetary ring gear against rotation The forward clutch application locks the turbine shaft and transmission main shaft together so that they rotate as a unit The low sun gear is splined to the m a i n shaft and rotates with it and in turn rotates the low planetary pinions The pinions are p a r t of the low carrier assembly which is splined to the transmission output shaft With the low ring gear held stationary by the applied low clutch and the low sun gear rotating the pinions the low planetary carrier must rotate within the ring gear and
50. positions Diston spring REMOVAL AND INSTALLATION OF SLAVE PISTON Remove spring retainer springs and slave piston Reassemble components using same procedure as when removed Be sure retainer Is in same position as shown in picture 10 REMOVAL AND INSTALLATION OF MASTER RECOMMENDED TORQUE VALUES PISTON PART NAME TORQUE Y 7 Exhaust Valve Bridge Adjusting Screw Locknuts 20 25 Ib ft 27 34 Nem sgt i Fuel Tube Nuts 12 15 Ib ft 16 20 Nem 2nd mx Injector Clamp Bolt 20 25 Ib ft 27 34 Nem F a ee Engine Brake Hold down Bolts 88 92 Ib ft 119 125 Nem A m Slave Piston Adjusting Screw Locknuts 15 18 Ib f 20 24 Nem SPRING DATA p i Slave Piston Spring Load at 1 39 in 35 3 mm 72 5 80 5 Ibs 323 358 N Part Number 1288 Load of 1 27 In 32 3 mm 82 5 91 5 Ibs 367 407 N Free length 2 36 In 60 mm Number of coils 10 3 4 approx Remove button head screw lock plate master Control Valve Spring Load at 81 in 20 6 mm 2 1 2 5 Ibs 9 11 piston spring and fork assembly from housing Part Number 1518 ck RE Ed lbs 25 28 N Number of cells 6 1 2 approx Control Valve Stop Spring Load at 81 In 20 6 mm 4 0 4 6 Ibs 18 20 N Part Number 1519 Load at 50 In 12 7 mm 8 5 9 5 lbs 38 42 N Free length 1 10 in 28 mm Number of coils 5 1 2 approx Withdraw master piston Reassemble components using same procedure as when removed JACOBS ENGINE BR
51. studied A detailed description is given in the Introduction of each Part of the manual to assist the user in finding the information required to operate or maintain the equipment Operator s Manual TM 5 4210 227 10 This manual is designed to provide the information necessary for a fire fighter or mechanic to properly operate the truck the pump and the ladder Maintenance Manual TM 5 4210 227 24 amp P This manual contains the information necessary for an experienced mechanic to maintain and repair all facets of the apparatus Each volume is individually indexed for ease of reference This manual contains all the information necessary to obtain assemblies and subassemblies or individual parts required to repair and maintain the fire truck NOTE The installation manual for Jacobs Engine Brake Model 71 92 and 71A 92A is presented on the following pages The second part of this volume consists of a commercial bound manual HT700F Series Engine Manual TABULATED DATA N A MAINTENANCE MANUAL SECTION I 1 INTRODUCTION TABULATED DATA 1 1 1 TM 5 4210 227 24 amp P Organizational Direct Support and General Support Maintenance Manual for 85 Aerial Ladder Fire Fighting Truck is divided into eight volumes These eight volumes are further subdivided into specific sections consisting of both Government and commercial literature 5 4210 227 10 Operator s Manual for the Aerial Ladder Fire Fighting Truck is one separate m
52. the second clutch produces third gear while the third clutch produces fourth gear b Description 1 The second and third clutches for all three models are composed of two identical pistons twenty one clutch plates 13 in second clutch 8 in third clutch and a center support 2 Two pistons 9 and 20 are separated by a wall in the center support housing assembly 15 Each piston is retained in its bore by twenty piston return springs 8 or 21 a return spring retainer 7 or 22 four selflocking retainer rings 6 or 23 and snaprings 5 or 24 3 Eight clutch plates are required for the third clutch f o u r internal splined and four external tanged plates The internal splined plates are splined to the outside diameter of the fourth clutch housing and are free to rotate The external tanged plates are anchored against rotation to the transmission housing 4 Thirteen clutch plates are required for the second clutch Six internal splined plates are splined to the outside diameter of the front carrier assembly and are free to rotate The seven external tanged clutch plates are anchored to the transmission housing and cannot rotate 5 The center support assembly is housed in the transmission and located by an anchor bolt This insures accurate oil passage hole alignment from the valve body to the second and third piston cavities C Operation of Third Clutch B foldout 14 All models 1 When hydraulic pressure is direct
53. the center support hub Attach lifting bracket J 24195 and install the center support assembly Align the tapped hole in the in the support to the hole transmission housing fig 7 17 Copyright 1983 General Motors Corp 7 9 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 6 Install the special 3 8 16 x 3 inch 2 1 4 inch in earlier models anchor bolt and plain washer finger tight Remove the lifting bracket Install the snapring selected in that retains the center support assembly fig 7 25 The gap of the snapring should be toward the top of the transmission regardless of its position when removed 8 Position the transmission rear upward and remove the two bolts and compressor bar from the adapter housing 7 7 INSTALLING REAR COMPONENTS 750CRD HT 754CRD 32983 utch snapring a Adapter Housing Low Clutch Low Ring Gear 1 Place the low ring gear flat side rear downward on a bench Install ten plates of the low clutch pack removed in or clutch pack selected by the stack method as follows Lay aside the first three plates from the piston end of the pack The plates laid aside should include two thick external tanged plates refer to Beginning with the fourth plate in the pack internal splined alternately install five internal splined and five external tanged plates onto the ring gear 2 Remove the adapter housing from the transmission housing Do not drop the first clutch piston J
54. upshifts occur at lower road speed when the throttle is closed and at higher road speed when the throttle is open 2 Rear governor pressure is dependent upon the rotational speed of the transmission output The greater the output vehicle speed the greater is rear governor pressure When rear governor pressure is sufficient the first upshift 1 2 HT 740D HT 747D HT 750CRD HT 754CRD or 2 3 HT 750DRD will occur A further increase in rear governor pressure and vehicle speed will cause a 2 3 or 3 4 upshift A still further increase in rear governor pressure will cause a 3 4 or 4 5 upshift Note that each of these upshifts will be either delayed or hastened by the decrease or increase respectively of modulator pressure Copyright 1983 General Motors Corp 2 22 DESCRIPTION AND OPERATION 3 In other drive ranges the same upshift sequence occurs until the highest gear attainable in that range selection is reached 4 In any automatic upshift the shift signal valve acts first This directs a shift pressure to the relay valve The relay valve shifts exhausting the applied clutch and applying a clutch for a higher gear r Automatic Downshifts 1 Automatic downshifts like upshifts are controlled by rear governor and modulator pressures Downshifts occur in sequence asrear governor pressure and or modulator pressures decrease Low modulator pressure open throttle will hasten the downshift high modulator press
55. z EEA Rae eee Yn a ae 1 3 4 SHIFT 2 3 SHIFT OCKUP FEED ON HIGH TORQUE RISE SEE SIGNAL VALVE SIGNAL VALVE MODELS LOCKUP CUTOFF VALVE EE ASSEMBLY OMITTED PRESSURE MANUAL SELECTOR VALVE 1 1 MODULATOR 2 DR2 NEUTRAL ACTUATOR 2 3 DR3 START SWITCH R4 25 440 9 5 DR ORIFICE REGULATOR VALVE OPEN ON HIGH REGULATOR TORQUE RISE MODELS FOURTH CLUTCH HOLD REGULATOR THIRD AND FOURTH CLUTCH FEED REVERSE 5 SIGNAL 27 ory REAR GOVERNOR n S ara H a es oot ES H TEOS REAP GOVERNOR TRIM GOVERNOR ACCUMULATOR m BOOST ACCUMULATOR ON idis om VALVE THIRD CLUTCH SECOND CLUTCH FOURTH CLUTCH RS css BS en TRIMMER VALVE TRIMMER VALVE TRIMMER VALVE LOCKUP CUTOFF VALVE ASSEMBLY TRIMMER USED ON CONVENTIONAL MODELS FIRST CLUTCH Hm Lo aa 53902 Foldout 7 Model 750DRD transmission hydraulic system no lockup in first gear schematic view Copyright 1983 General Motors Corp FOLDOUT 7 ORIFICE HT 740 HT 750D AUTOMATIC TRANSMISSIONS B main RETARDER IN C CONVERTER IN RETARDER QUT X Bl converter ouT LE UM HE ee gt KJ mooutator Front GOVERNOR 2 LUBRICATION First crutch
56. 0 143 5 to 164 8 oolid blue 17 0 107 0 611 2 45 1 97 39 41 to 48 21 2 69 15 5 62 2 50 0 175 3 to 214 4 oolid blue 18 5 0 092 0 535 2 38 1 97 2 9 to 29 9 white stripe 2 33 13 6 60 5 50 0 124 0 to 133 0 Solid white 10 0 054 0 490 1 47 0 80 11 9 to 13 1 orange stripe 1 37 12 5 37 3 20 3 52 9 to 58 3 Solid yellow 10 0 054 0 490 1 15 0 80 6 01 to 7 15 1 37 12 5 29 2 20 3 26 7 to 31 8 Blue stripe 10 0 054 0 490 1 27 0 80 8 39 to 9 03 1 37 12 5 32 3 20 3 37 3 to 40 2 Solid blue 10 0 054 0 490 1 36 0 80 9 88 to 10 92 red stripe 1 37 12 5 34 5 20 3 44 0 to 48 6 Solid white 10 0 054 0 490 1 47 0 80 11 9 to 13 1 orange stripe 1 37 12 5 37 3 20 3 52 9 to 58 3 Solid blue 8 5 0 092 0 690 1 45 1 10 20 70 to 25 30 white stripe 2 34 17 5 36 8 27 9 92 52 to 112 5 Solid yellow 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 blue stripe 2 33 17 5 42 9 27 9 145 0 to 177 0 Copyright 1983 General Motors Corp 8 7 Fold out Ref Spring 20 B 29 Third clutch trim mar valve secondary 20 30 Third clutch trimmer valve primary 20 B 34 First clutch trimmer valve secondary 20 B 35 First clutch trimmer valve primary Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Part No 6885166 6833938 6833945 6839271 6880045 6880118 23012937 6839102 6880274 6884701 6885166 6833938 6833945 6835730 6837693 Table 8 2 SPRING D
57. 0 092 0 930 2 27 1 65 17 5 to 20 5 2 33 23 6 57 7 41 9 77 8 to 91 2 8 5 0 114 0 940 2 16 1 94 12 2 to 14 8 2 89 23 9 54 9 49 3 54 3 to 65 8 8 5 0 113 0 940 1 97 1 10 50 4 to 55 6 2 87 23 9 50 0 27 9 224 2 to 247 3 8 8 WEAR LIMITS AND SPRING DATA Table 8 2 SPRING DATA cont Spring Free Mean dimension shown 8 9 Copyright 1983 General Motors Corp Fold Color No Wire dia OD Length Length Under Load out Ref Spring Part No Code Coils 1n mm 1n mm 1n mm 1n mm 16 35 First clutch trimmer 6839026 Solid blue 7 0 092 0 930 1 85 1 10 23 5 to 27 5 valve primary yellow stripe 2 33 23 6 47 0 27 9 104 5 to 122 3 6839271 Solid white 10 0 103 0 940 2 56 1 94 20 to 22 yellow stripe 2 60 23 9 65 0 49 3 89 0 to 97 9 6880045 oolid orange 8 0 099 0 940 2 18 1 94 6 2 to 7 4 2 51 23 9 55 4 49 3 27 6 to 32 9 6880118 Solid blue 8 5 0 092 0 690 1 45 1 10 21 70 to 25 30 white stripe 2 32 17 5 36 8 27 9 96 5 to 112 5 23013754 Solid red 8 5 0 113 0 940 2 16 1 94 12 2 to 14 8 2 87 23 9 54 9 49 3 16 5 to 20 1 39 Second clutch trimmer 6833940 Solid blue 87 0 121 0 940 2 16 1 65 37 8 to 45 8 valve secondary orange stripe 3 07 23 9 54 9 41 9 168 1 to 203 7 6838532 Solid white 8 5 0 121 0 950 2 10 1 10 78 3 to 85 7 3 07 24 0 53 3 27 9 348 3 to 381 2 6839102 Solid red 8 5 0 092 0 780 1 68 1 10 32 6 to 39 8 2 33 19 8 42 7 27 9
58. 13 bolts and lockwashers evenly spaced fig 7 9 Tighten the bolts to approximately 30 Ib ft 41 Mm 6 Invert the transmission front upward Using gage J 24194 check the clearance between the low clutch plates 7 10 It is recommended the gage be placed between the adapter housing wall and the first steel plate The prescribed clearance is 0 095 to 0 145 inch 2 41 to 3 68 mm Any dimension within 0 095 to 0 145 inch is satisfactory However the closer the clearance is to 0 095 Inch the longer the interval between clutch plate replacements will be Replace worn clutch plates with new plates to establish the desired clearance Recheck the clearance as described above 7 Using gage J 24194 check the clearance between the first clutch plates fig 7 11 It is recommended the gage be placed between the 51026 transmission housing and the first steel plate Fig 7 10 Checking low clutch clearance HT prescribed clearance is 0 095 to 0 145 inch 2 41 to 3 68 mm Any dimension within 0 095 to 0 145 Inch is satisfactory However the closer the clearance is to 0 095 inch the longer the interval between clutch plate replacements will be Replace worn clutch plates with Copyright 1983 General Motors Corp 7 5 750CRD DRD HT 740D HT 750D AUTOMATIC TRANSMISSIONS add Fig 7 11 Checking first clutch clearance HT 750CRD DRD HT 754CRD b Selecting Center Support Snapring NOTE If the stack
59. 19 CENTER SUPPORT ASSEMBLY a Disassembly foldout 14 1 Place center support housing assembly 15 Bjfoldout 14 vertically upright on the work table 2 Remove pistons 9 and 20 with attached parts 3 Remove inner seal ring 10 and 19 and outer seal ring 11 and 18 from piston 9 and 20 RETAINER WASHER THIRD CLUTCH PISTON adip Fig 6 53 Removing self locking retainer washers 4 If replacement is necessary disassemble the two piston assemblies Cut retainer rings 6 and 23 to prevent damaging the piston projections fig 6 53 b Remove the retainer rings retainers 7 and 22 and springs 8 and 21 from pistons 9 and 20 6 Remove sealrings 12 and discard Remove thrust bearing race 14 and needle bearing 13 from the hub of center support housing 17 7 Determine the serviceability of the seal ring grooves on the center support hub Insert do not force gage J 29198 3 into a groove on the support hub Rotate the gage 360 degrees around the hub f the gage does not rotate freely the support is damaged and should be replaced NOTE A damaged or worn center support hub can be salvaged with guidance from the instructions the instruction sheet in the Sleeve a n d Pin Kit The Kit contains one unfinished center support sleeve one sleeve retainer pin and one machining and installation instruction sheet Refer to Parts Catalog SA 1268 for the Kit part number 8 If bushing replacement is n
60. 24195 CENTER SUPPORT 3 Place the adapter housing with piston upward over the assembled low ring gear and clutch plates 4 Install the adapter housing gasket onto the adapter housing aligning the holes in the gasket with those in the housing Retain the gasket with oil soluble grease 5 Grasp the assembled adapter housing ring gear and clutch plates invert the assembly and install it onto the rear of the transmission housing as follows 6 Align the adapter housing dowel pins Fig 7 17 Installing center support with proper holes in the transmission housing Lower the adapter housing until the Copyright 1983 General Motors Corp 7 10 ASSEMBLY OF TRANSMISSION internal teeth of the low ring gear begin to mesh with splines on the rear planetary carrier hub Support the adapter housing while meshing the low ring gear by tapping with a soft mallet When mesh is complete seat the adapter housing 7 Install the three remaining low clutch plates laid aside in 1 above Install the plates in external tang internal spline external tang sequence fig 7 18 b Low Planetary Rear Cover Assembly 1 Install the low planetary carrier by carefully aligning the teeth of the four pinions with those of the low ring gear fig 7 19 CAUTION Do not lift the low carrier by the ball bearing The bearing may be loose permitting the assembly to drop 2 Place the rear cover gasket onto the rear cover Retain
61. 27 102 NM erc HT 740D HT 750CRD 750080 HT 750DRD DB 2 2 1616 6 840 Ib 940 Ib 940 Ib 1375 Ib CT 381 kg 426 kg 426 kg 624 kg Retarder package 190 Ib 190 Ib 190 Ib 190 Ib housing rotor valve body 86 kg 86 kg 86 kg 86 kg Power takeoff package 120 Ib 120 Ib 120 Ib 120 Ib converter hsg drive 55 kg 55 kg 55 kg 55 kg driven gears Transfer gear housing ccccccseeeseeeceeeeeeeeaeeeneeeseeeeaees 590 Ib 250 kg Power takeoff mounting optional Converter driven PTO 10 o clock position as viewed from rear M nt ng flage 9 12 22 992 999 094 0 99 SAE 6 bolt Intermittent rating eseeseeeeeeenrenn n 400 Ib ft 543 Nem C OBEBBIBIOUSEOUTIO 300 Ib ft 407 Nem Dive dgeardata 6 pitch 20 pressure angle 78 teeth Engine driven PTO Top mounting 1 o clock position as viewed from rear MOUNTING TAG reos 25222522229222 0224 2 4220 2 002 0 42 SAE 8 bolt Intermittent rating 2 292 nir nica Mus BhasBEun Rat Maas 260 hp 194 kW
62. 3 relay valve The unit is now in first gear Automatic shifting from first gear progressively to higher gears second third fourth fifth will occur when vehicle speed increases The highest gear attainable in automatic shifts is determined by the range selected refer to 7 below Copyright 1983 General Motors Corp DESCRIPTION AND OPERATION 5 Shifting the selector valve from neutral to reverse R charges t h e fourth clutch while the low clutch remains applied In reverse fourth clutch reverse signal pressure is also directed to the bottom of the 2 3 relay valve The pressure at this point prevents the relay valve from moving downward during reverse operation 69 When the circuits are charged as described for the shift to drive 5 D5 above any forward shift from first to second second to third third to fourth and fourth to fifth can occur automatically These shifts occur as a result of rear governor pressure At less than full throttle modulator pressure will assist governor pressure 7 Position of the selector valve determines the highest gear which will be normally reached automatically In drive 5 D5 automatic 1 2 2 3 3 4 and 4 5 shifts can occur In drive 4 D4 automatic 1 2 2 3 and 3 4 shifts can occur In drive 3 D3 automatic 1 2 and 2 8 shifts can occur In drive 1 DI no upshift can occur unless overspeed occurs Automatic downshifts can occur within the selected ranges NOTE Mo
63. 57 0 063 1 60 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 Copyright 1983 General Motors Corp Spring OD in mm 0 640 16 3 0 672 17 0 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 Free Length in mm 2 51 63 8 1 99 50 6 2 43 61 7 2 53 64 3 2 75 69 9 2 85 72 4 2 98 75 7 2 62 66 6 2 55 64 8 2 82 71 6 2 44 61 9 2 57 65 3 2 65 67 3 2 73 69 3 2 78 70 6 2 86 72 6 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 Length Under Load in mm Ib N 10 75 to 11 25 47 8 to 50 0 8 22 to 8 72 36 6 to 38 8 11 45 to 11 95 50 9 to 53 2 12 25 to 12 75 54 5 to 56 7 9 25 to 9 95 41 1 to 44 3 9 85 to 10 55 43 8 to 46 9 10 60 to 11 40 47 2 to 50 7 8 50 to 9 10 37 8 to 40 5 8 10 to 8 70 36 0 to 38 7 9 65 to 10 35 42 9 to 46 0 7 45 to 8 05 9 9 to 10 9 8 2 to 8 8 36 5 to 39 1 8 65 to 9 35 11 7 to 12 7 9 15 to 9 85 40 7 to 43 8 9 4 to 10 1 41 8 to 44 9 9 9 to 10
64. 6832462 6833935 6833941 6833942 6834576 6834528 6834902 6884940 6884943 6884944 Color Code Green stripe Solid white green stripe oolid blue green stripe oolid orange green stripe Solid yellow green stripe oolid blue yellow stripe Solid red Solid blue oolid blue white stripe Solid white oolid orange yellow stripe oolid blue yellow stripe oolid orange Solid yellow orange stripe Solid white orange stripe oolid blue red stripe No Coils 8 17 WEAR LIMITS AND SPRING DATA Table 8 2 SPRING DATA cont Wire dia in mm 0 062 1 57 0 062 1 57 0 054 1 37 0 054 1 37 0 059 1 50 0 054 1 37 0 072 1 83 0 054 1 37 0 062 1 57 0 054 1 37 0 054 1 37 0 073 1 85 0 059 1 50 0 054 1 37 0 056 1 42 0 054 1 37 Copyright 1983 General Motors Corp Spring OD in mm 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 690 17 5 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 680 17 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 Free Length in mm 2 45 62 2 2 59 65 8 2 94 60 9 2 98 75 7 2 51 63 8 2 73 69 3 2 18 55 4 2 17 55 1 2 15 54 6 2 50 63 5 2 39 60 7 1 52 38 6 2 41 61 2 2 53 64 3 2 65 67 3 2 69 68 3 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 20
65. 7 B were removed install new studs oversizes are available if required 12 Select s t u d which when installed to project 5 47 to 5 53 inches 138 9 to 140 46 mm will tighten to 15 65 Ib ft 20 88 N m 6 12 CONVERTER HOUSING WITH 8 BOLT TOP COVER RETARDER PLATE OIL PUMP a Disassembly 1 Refer 6 10 1 through 5 for removal of the oil pump Note that the oil pump includes two driven gears 2 Remove the sealring from the groove in the retarder plate 3 Remove nineteen bolts retaining the retarder plate fig 6 31 4 Remove the retarder plate and gasket from the converter housing fig 6 32 5 Remove the four test plugs from the converter housing fig 6 32 6 Remove the three studs from the converter housing if replacement is necessary 31 7 On earlier models if the side spindle must be removed remove the bolt and washers from the rear of the spindle Press the spindle rearward 8 Position the housing front upward Remove eight bolts that retain the ground sleeve 33 9 Remove the ground sleeve a 1 T nro n ATC aN Y RETARDER PLATE M fe 1 4 ASSEMBLY RETARDER PLATE M J CONVERTER HOUSING X ee ee J er tA Edi mr n n t B PLUG re Rut a Nate a ark Pays ames d TAM D O N ys 1 o 6 a Fig 6 32 Removing or installing retarder plate assembly
66. A 23 Lockwasher 1 2 2 24 Lockwasher 1 2 3 25 Bolt 1 2 13 x 1 3 8 3 A 26 Governor assy 1 0 462 19 Gear and hub assembly 20 Bushing 21 Thrust race 22 Needle roller bearing 23 Thrust race 24 Thrust race 25 Needle roller bearing 26 Thrust race 2 Low planetary ring gear 28 Ball bearing 29 Low planetary carrier assembly 30 Low planetary carrier 31 Pinion pin 4 32 Bronze thrust washer 8 33 Pinion 4 34 Needle roller bearing 4 35 Steel thrust washer 8 27 Governor pin and gasket assy 28 Governor gasket 29 Governor pin 30 Governor cover 31 Bolt 5 16 18 x 9 16 4 C 32 Output shaft assy 33 Output shaft and bushing assy 34 Bushing 35 Output shaft 36 Cup plug 3 Needle bearing assy 38 Output shaft assy 39 Cup plug 40 Output shaft and bushing assy 41 Output shaft 42 Bushing 43 Nut 2 16 D 44 Transfer housing gasket Torque Ib ft Nem A 67 80 91 108 B 10 12 14 16 C 10 13 14 17 D 600 800 813 1085 FOLDOUT 19 HT 740D HT 750D AUTOMATIC TRANSMISSIONS A Foldout 19 Adapter housing low clutch plates and low carrier HT 750DRD exploded view 4 L a m n Copyright 1983 General Motors Corp B Foldout 19 Low clutch piston rear adapter housing and governor exploded view 1 External snapping 2 Spring retainer 3 Piston release Spring 30 4 Low clutch pi
67. ADD and FULL marks the oil level is safe for operating the vehicle If it registers on or below the ADD mark add the required amount of oil necessary to bring the oil level mid way between the ADD and FULL marks Approximately one 1 quart 0 9 liters of oil is required to move the oil level from ADD to mid way between the ADD and FULL marks on the dipstick 5 Hot Oil Check HOT RUN band Be sure the temperature has reached 160 to 200 F 71 93 With the engine idling and the transmission in neutral remove the dipstick from the oil filler tube and check the oil level If the oil level registers in the HOT RUN band fig 3 3 the quantity of oil in the transmission is safe for operating the vehicle If it registers on or below the bottom line of the Hot Run band add the required amount of oil necessary to bring the oil level to the middle of the hot run band Approximately one 1 quart 0 9 liters of oil is required to move the oil level from the bottom line of the HOT RUN band to the middle of the HOT RUN band e Dropbox Oil Check 1 Transmissions equipped with a transfer gear housing dropbox have two independent oil circuits the transmission circuit and the dropbox circuit Each circuit requires a different type and grade of oil and must be checked and serviced independently 2 Park the vehicle on level ground shift to neutral and apply the parking brake 3 If the dropbox has a fill tube level indicator r
68. Clutches PISLOTIS 4 14 D Parts EUbIICallOELass ionic 4 14 c External Plugs Hydraulic mpi jo o POEM 4 14 d Grease Used for Assembly 4 14 Sealring Compounds Nonsoluble Greases Lip type Oil Seals Butt joint Sealrings Interference fit Parts Sleeve type Bearings Bearings Ball or Roller gt 4 7 REMOVING OR INSTALLING TRANSMISSION d Drain Oil b Check Linkages and Lines c Clean Transmission d Reconnect at Installation 4 8 WEAR 4 9 SPRING SPECIFICATIONS 4 16 TORQUE SPECIFICATIONS 4 16 DISASSEMBLY OF TRANSMISSION 5 1 SCOPE 5 1 5 2 REMOVING EXTERNAL COMPONENTS a Mounting Transmission In OV Crea a 5 1 b Removing External COMPONENTS umo Np S 5 1 REMOVAL OF MANUAL OUTPUT DISCONNECT ASSEMBLIES DROPBOX 1 5 2 5 4 SEPARATING DROPBOX FROM TRANSMISSION a Removal of Transfer Gear RENI 5 2 5 5 REMOVING REMOTE COVER FLYWHEEL AND LOCKUP CLUTCH a Removing Remote Front GY NOTET 5 3 b
69. FORWARD CLUTCH CONVERTER IN ua FORWARD REGULATOR n az L d a p D d Lond a 1 moe 1 aem D nd Cuna GR Ld i i i CLOSED ON 2ND GEAR MODULATOR START i E MODULATOR CA L CLOSED PRESSURE REGULATOR MODULATOR PRESSURE f LOCKUP FEED OEN MECHANICA i FOR HIGH TORQUE L DRI PRESSURE RISE TRANSMISSIONS HIGH TORQUE RISE b MODELS WITHOUT LU CLUTCH MAIN LOCKUP MODULATION EXTERNAL TAPS IN CONVERTER ws HOUS ING t ce 2 SHIFT SIGNAL VALVE C CONVERTER IN CLUTCH 34 3 4 SHIFT EARLY MODELS TRIMMER REGULATOR SIGNAL VALVE Am E li z DRIVE 1 MB CONVERTER OUT 1 LUBRICATION 2ND GEAR START EARLY MODELS 2 3 LOCKUP CUTOFF VALVE FOURTH CLUTCH PRESSURE TAP BREITER BL LUBRICATION FEED t Lu REAR GOVERNOR l FRONT GOVERNOR E First autech BL FORWARD REGULATOR IL MODULATOR tocxuP FEED TRIMMER REGULATOR C EXHAUST OR SUMP Mr ens oe OO ee ee 1 anh 3 4 SHIFT m FORWARD REGULATOR NE SS E DR1 PRESSURE SNNNNNNNNNNN c S 1 2 SIGNAL RRESSURE ORIFICE 2 3SIGNAL PRIORITY VALVE by r XI M X ARBRE ae T H T N 1 2 SHIFT SIGNAL VALVE i LATE MODELS 1 ME 5
70. Internal snapring Fig 6 65 Components of gear unit and main shaft assembly HT 750DRD DRD DB 2 If bushings 24 and 26 A foldout 16 were damaged or removed from sun gear and shaft 25 refer paragraph 6 20 b 3 Install bearing race 15 fig 6 65 flat side first onto the rear of center planetary ring gear 13 Retain it with oil soluble grease Install needle roller bearing 16 onto race 15 Retain the bearing with oil soluble grease Install thick flat bearing race 17 onto bearing 16 Retain it with oil soluble grease 4 Install rear planetary sun gear 14 fig 6 into the rear of center planetary ring gear 13 Retain it with snapring 12 5 Install m a i n shaft 11 into the front of sun gear 14 Retain it with snapring 18 6 Install rear planetary carrier assembly 20 into the rear of planetary connecting drum 19 Retain it with snapring 21 7 Install shaft 11 with attached parts 12 through 18 into rear planetary carrier assembly 20 8 Install center planetary carrier assembly 10 into planetary connecting drum 19 Install thrust washer 9 and sun gear and shaft assembly 8 into center planetary carrier assembly 10 9 Install front planetary ring gear 7 outer splines first into the front of planetary connecting drum 19 Retain gear 7 with snapring 6 10 Install thrust washer 5 onto the rear hub of front planetary carrier assembly 4 Retain it with oil soluble grease 11 Install front
71. La DE a m um os i A hee edad by SR mW v n 23 SE 7 E EJ DE vun 2920 Figure 6 2 Removing or installing lockup clutch backplate 2 Using two prybars cushioned to prevent scratching the parts remove the torque converter turbine from the flywheel fig 6 1 3 Remove ball bearing 6 A foldout 10 from torque converter turbine assembly 8 only if replacement is necessary 4 Remove the lockup clutch back plate from the flywheel Remove the key from the flywheel bore 5 Remove the lockup clutch plate 6 2 6 Remove the lockup clutch piston 6 3 Remove the sealring from the piston outer groove Copyright 1983 General Motors Corp 6 1 HT 740D HT 750D SERIES TRANSMISSIONS 7 Remove the sealring from the inner hub of the flywheel fig 6 3 8 If replacement is necessary remove starter ring gear 11 9 from flywheel 12 after noting whether the gear tooth chamfers are toward the front or rear of the flywheel 9 If the sealring surface of the flywheel bore is worn beyond 1 007 inches diameter rework the bore and install a sleeve P N 6881519 as shown in 10 Cool the sleeve in dry ice for at least thirty minutes before installing Proper alignment during installation is necessary to prevent damaging the bore and sleeve 11 Press the sleeve flush with surface X fig 6 4 Be sure the internal chamfer is toward the rear side of the fl
72. MAIN PRESSURE IN ALL RANGES Low oil level Oil filter element clogged Sealring at oil intake pipe filter output leaking or missing Main pressure regulator valve spring weak Control valve body leakage Valves stuck trimmers relays and main pressure regulator Oil pump worn or damaged Remedy Clean or replace governor Back off spring adjusting ring Overhaul valve body assembly para 6 4 Refer to paragraph 3 12 Clean or replace governor Replace governor Tighten spring adjusting ringl para 6 4 Clean or replace modulator valvel para 6 4 Refer to paragraph 3 12 Add oil to proiper level para 3 3 Replace filter Replace sealring Replace spring Replace or rebuild valve body assembly Overhaul valve body assembly main pressure regulator valve Replace or rebuild oil pump LOW MAIN PRESSURE IN ONE OPERATING RANGE NORMAL IN OTHER RANGES Leakage in clutch apply circuits for specific range Excessive leakage at clutch piston seals for specific range EXCESSIVE CREEP IN FIRST AND REVERSE GEARS Idle throttle setting too high vehicle manual LOW LUBRICATION PRESSURE Oil level low Excessive internal oil leakage lubrication valve seat and spring low main pressure refer to C Cooler lines restricted or leaking Lubrication valve spring weak 1 2 Replace or rebuild valve body assembly Overhaul transmission and replace piston seals Adjust throttle setting refer to Add oil to proper level
73. Needle roller bearing assembly 16 Rear planetary sun gear 17 Planetary connecting drum 18 External snapring 19 Roller bearing race 20 Rear planetary carrier assembly 21 Internal snapring Fig 6 57 Components of gear unit and main shaft assembly HT 740D 8 Remove snapring 18 and remove main shaft assembly 12 from rear planetary sun gear 17 If orifice plug 35 A requires replacement remove it 9 Remove snapring 11 fig 6 57 and separate ring gear 13 and sun gear 16 10 Remove thrust race 14 needle bearing 15 and thrust race 19 11 Remove snapring 21 Remove rear planetary carrier assembly 20 from planetary connecting drum 17 f rear planetary carrier assembly requires rebuild or if bearing replacement is necessary remove ball bearing 47 A Refer to for rebuild of the rear planetary carrier assembly NOTE Refer to above b Replacing Sun Gear Shaft Bushings Aj foldout 15 1 If bushings 24 and 26 were removed install new bushings as follows 2 Apply Loctite Sleeve Retainer 601 or equivalent and position bushing 24 at bore of shaft 25 Aline interlock split so that it is more than 45 degrees from the swaging hole in the shaft Copyright 1983 General Motors Corp 6 39 HT 740D HT 750D SERIES TRANSMISSIONS 2 BUSHING PRESS IN TO DIMENSION SHOWN 2 PLACES USING TOOL J 24201 0 250 in 6 35 mm DIA HOLE 500 c Ib N 2 0030 in 50 876 mm 2 0015 in 50 8
74. OIL PAN WITH 6 INCH DEEP PAN DIMENSIONS ARE iN INCHES MILLIMETRES WITH 7 8 1 2 INCH DEEP PAN PROCEDURE USE HOT RUN BAND FOR 160 200 F 71 93 USE COLD RUN BAND FOR 60 120 F 16 49 C 16399C Fig 3 3 Transmission oil dipstick markings Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSIVIISSIONS FILL PIPE ANO LEVEL INDICATOR 16088 Fig 3 4 Dropbox oil level front view shaft The Add mark should be 3 inches 75 mm below a horizontal line through the center of the output drive shaft The dropbox ADD FULL marks are these same dimensions below the horizontal centerline of the output shaft for any mounting angle of rotation 0 15 30 45 or 60 3 4 OIL LEVEL CHECKS a Importance of Proper Level Maintaining the proper oil level is very 1 important If during check procedure e below inconsistent dipstick readings occur look for proper venting of the transmission breather para 3 9 and or proper venting of the oil filler tube 2 Always check the oil level on the dipstick at least twice Consistency is important in maintaining accuracy CAUTION The oil level rises as the sump temperature increases Do not add oil to the transmission until a normal operating temperature is reached e 4 5 6 Add the required amount of oil to bring the oil level to the Full Hot Run band or the Cold Run band marks 3 Do not overfill the
75. REGION Detroit Diesel Allison Europe Div of GM Continental S A Nederland Parmentierplein 1 3088 GN Rotterdam Mail P O Box 5061 3008 AB Rotterdam Netherlands Phone 010 290 000 Telex 28355 GMCNL ASIA REGION Detroit Diesel Allison Div of GM Oversea Corp 15 Benoi Sector Jurong Town Singapore 2262 Phone 65 265 4697 or 65 261 0801 Telex RS 21608 A B GM SING MIDDLE EAST AFRICA REGION Detroit Diesel Allison Athens Towers A Bldg eth Floor Messoghion 2 4 Athens 610 Greece Phone 30 1 770 6669 30 1 778 5344 30 1 778 7281 Telex 215759 DDA PACIFIC REGION Detroit Diesel Allison Australia Div of GM Overseas Corp Princes Highway P O Box 163 Dandenong Victoria 3175 Australia Phone 61 3 797 7911 Telex AA30792 HT 700D SERIES TRANSMISSIONS Step Three If you are still not satisfied present the entire matter in writing or by phone to the product headquarters Allison Transmission Operations Manager 700 Series Transmissions Service Detroit Diesel Allison P O Box 894 Indianapolis Indiana 46206 Phone 317 242 3531 The inclusion of all pertinent information will assist the Home Office in expediting the matter If an additional review by the Home Office of all the facts involved indicates that some further action can be taken the Regional Office will be so instructed If at this point your problem is still not resolved to your satisfaction call or write Manager Tran
76. Removing Flywheel Lockup 5 4 Paragraph Page 5 6 REMOVING OIL PAN FILTER VALVE BODY HT 740D HT 747D a b Oil Pan 5 5 Valve BOOY 2 6 5 7 REMOVING OIL PAN FILTER VALVE BODIES HT 750D 754D a b Oil Pan Filter aeree 5 6 Valve Bodies 5 6 5 8 REMOVING TORQUE CONVERTER AND PTO COMPONENTS a b Converter Stator 5 9 Scavenge Pump Assembly 5 11 Power Takeoff 5 11 5 9 REMOVING CONVERTER HOUSING a Housing with 2 Bolt Top Cover no 1 b Housing with 2 Bolt Top Cover with c Housing with 8 Bolt Top Cover no retarder d Housing with 8 Bolt Top Cover with retarder 5 10 REMOVING RETARDER VALVE BODY HOUSING AND FRONT SUPPORT AND SLEEVE ASSEMBLY a Retarder Valve Body Assembly o cescececsessessessessesseesessereerearees b Retarder Housing and Front Support and Sleeve Assembly eseeeennnes 5 11 REMOVING FORWARD FOURTH THIRD CLUTCHES a Forward Fourth Clutches 5 15 b Third Clutch seeeseesees 5 15 5 12 REMOVING CENTER SUPPORT GEA
77. The low planetary gear set is located behind the gear unit and main shaft assembly Refer to It contains a sun gear a carrier assembly and a ring gear The sun gear is splined to the main shaft and the rear carrier is splined to the low ring gear thereby interconnecting the four planetary systems 5 This interconnection of the planetary input reaction and output elements and connections with the forward and fourth clutches produces five forward speeds and one reverse speed b Operation foldout 15 1 Ihe front planetary assembly 5 used in conjunction with the center planetary assembly 16 produces third gear when the forward and second clutches are applied fig 2 11 2 The center planetary is active in third fourth fifth and reverse gears 3 Ihe rear planetary carrier assembly 38 is active in second third fourth and fifth gears In second gear with the application of forward and first clutches it transmits torque at a reduction through the low carrier to the output shaft In third fourth a n d fifth gears its only function is in the transmitting of torque through the low carrier to the output shaft 4 The low planetary carrier assembly 18 B foldout 18 is active in all gears With the application of the forward clutch with any one of the other clutches low first second third fourth torque is transmitted via main a and planetary carrier components ref para 2 28 through the low carrie
78. a new bearing flush with to 0 010 inch 0 25 mm below the outside surface of plate 13 7 Install p u m p drive gear 5 into body 9 and install lock roller 6 into its groove in the shaft of gear 5 Install internal drive gear 11 onto the shaft of gear 5 aligning the lock roller with the groove in the gear Secure the gear with snapring 12 8 Install plate 13 onto body 9 snaprings 15 onto spindles 10 Install 6 15 RETARDER VALVE BODY ASSEMBLY a Disassembly Bj foldout 21 1 Remove two bolts and washers 22 and 21 from bottom of valve body 13 2 Remove cover 20 and gasket 19 3 Slide valve 14 out through bottom of valve body 13 4 Remove snapring 18 washers 15 and 17 and spring 16 from valve 14 5 For replacement remove wiper 10 seal 11 and snapring 12 NOTE Refer to above b Assembly B foldout 21 1 If removed for replacement install snapring 12 new seal 11 with lip toward inside of valve body and wiper 10 with scraper edge outside valve body 13 Copyright 1983 General Motors Corp 6 26 REBUILD OF SUBASSEMBLIES 2 Install washer 15 on bottom end of valve 3 Install spring 16 a n d washer 17 on valve 14 and secure with snapring 18 4 Install gasket 19 a n d cover 20 with two bolts 22 and two lockwashers 21 Tighten bolts to 2 32 Ib ft 35 43 N m 5 Check the stroke of the retarder valve It should be 1 1 2 inches 38 1 mm 14 6 16 RETARDER HOUSING FRONT SUPPORT a D
79. above onto the rear of main shaft assembly 12 The counterbore in gear 16 must be toward the rear of shaft assembly 12 Retain the sun gear with snapring 18 recessed in the gear counterbore 4 If ball bearing 47 foldout 15 was removed press a new bearing onto the Fig 6 63 Machining front bushing in sun gear shaft assembly c m ae tig 1 LEA i xl m ua l H T a REAMER AND ACT i 20480 i nd am Mw AR i j lisa Ta ITA AME MERI Hi a i Co i 3 34 A PILOT TOO e vl e oy eb a 28189 1 E p TE a B 5 Fig 6 63 Machining front bushing sun gear shaft assembly rear planetary carrier assembly Seat it firmly against the hub shoulder b Apply oil soluble grease to both thrust bearing races 14 and 19 ifia 657 and needle bearing 15 Install race 19 inner lip first into the front bore of rear planetary carrier assembly 20 Install race 14 flat side first onto the rear of center planetary ring gear 13 Install needle bearing 15 onto race 14 Install main shaft 12 and attached parts into the front of rear planetary carrier assembly 20 Install thrust washer 8 onto the main shaft 6 assembly 7 Install sun gear and shaft assembly 7 onto the main shaft larger end first 8 Install center planetary carrier assembly 10 small diameter first into center planetary ring gear 13 an
80. eight steel b a 11 s in fourth clutch housing 14 Make sure they are securely staked in the housing and are free to move without restriction AS i oong soi DE Wo cM a TN AR HUB us GL REA R WUE E ed n v ed an nae gu rra qur cn MET y TE I D a s et Bex HOUSING We VAR FT y H em Fe Fig 6 47 Removing or installing fourth clutch rear bearing race Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS BACKPLATE di nt al Te AR r it 3 3 pea D Tix a 7 i i V Svan ol a ior x per De dt pA MOS A 1 ta Exe ndr i s eee eee al MS MX ab ELT 2454 oro n Pri E TI ii b d E T Ats ie AA aa F n ob 21 LLAR cig nem EL apay mirs ium REM uut a REM emm us js ame i UG i T RUN T uM Mex n er AEN Du isa e Hr RUPEE aret evel peace INTERNAL EXTERNAL SPLINED TANGED PLATE PLATE oP RING 20 NAPRING i PISTON SNAPRING Hi fi L i i Vi EXTERNAL SPRING T TANGED HETAINER PLATE sigs Fig 6 48 Removing or installing fourth clutch plates BAR STUD ASS Y ae 24201 2 AEN E phu pr dE ee COMPRESSOR ar E nee Pier i HE M fe age iori C me 24204 3 a 1 C
81. failure Refer to for proper installation procedures 2 Install the butt joint sealrings onto the front support hub Install a 1 2 13 x 7 inch headless guide bolt into a tapped hole in the front of the transmission housing 3 If pitot blocker 27 A is used install it onto the rear of the front support at rear of retarder housing Retain the block with two screws 18 B foldout_12 and washers 17 Tighten the screws to 5 4 b ft 4 5 Nem If installed disregard steps 3 and 6 below 4 Install two 10 32 x 6 inch guide screws J 6889 1 into the pitot tube The exit port between tapped holes of the pitot tube must face toward the guide screws fig 7 42 Position the guide screws and pitot tube in the pitot collector ring so that the entrance port of the tube faces outward toward lip of collector ring fig 7 42 5 Position the retarder housing assembly fig 7 42 so that the flat outer side is toward the right side of the transmission 6 Lower the retarder housing engaging the guide bolt with the proper bolt hole in the housing Then continue to lower the housing until the pitot tube guide screws enter the pitot tube screw holes Seat the retarder housing on the transmission housing Drop a 1 2 x 6 inch bolt into a hole opposite the 7 inch guide bolt and align the housing until the 6 inch bolt drops freely through the hole in the transmission housing front flange 7 Install screws 18 B foldout 12 and washe
82. fig 7 16 b Center Support 1 Install the third clutch piston assembly into the center support The lips of the sealring must be toward the cavity in the center support Copyright 1983 General Motors Corp 7 12 ASSEMBLY OF TRANSMISSION HOIST T DN iii 1 24196 MAIN SHAFT i GEAR UNIT av dee Fig 7 23 Installing gear unit assembly HT 740D HT 747D HT 750DRD CAUTION Improper installation of butt joint sealrings may cause transmission failure Refer toj paragraph 4 6g for proper installation procedure 2 Install the butt joint sealrings onto the center support hub Attach lifting bracket J 24195 and install the center support assembly Align the tapped hole in the support to the hole in the transmission housing fig 7 24 CAUTION The center support is fitted to the transmission housing with very little clearance It may bind during installation if the housing is cold Heat the housing slightly if necessary Do not use a torch to heat the 1 24195 CENTER SUPPORT Fig 7 24 Installing center support housing A sun lamp or a current of warm air is sufficient 3 Install the special 3 8 16 x 3 inch 2 1 4 inch on earlier models anchor bolt and plain washer finger tight Remove the lifting bracket 3 Install the snapring selected in that retains the center support assembly fig 7 25 gap of the snapring should be towar
83. fig 7 22 6 Install the governor cover gasket and cover and retain them with four 5 16 18 x 9 16 inch bolts Tighten the bolts to 10 13 Ib ft 14 17 Nem NOTE Continue assembly of Model HT 750CRD HT 754CRD at paragraph 7 11 7 8 INSTALLING GEAR UNIT SECOND CLUTCH CENTER SUPPORT HT 740D a Gear Unit Second Clutch Hemove the center support anchor bolt Refer to fig 7 39 Remove the special selective snapring that retains the OUTPUT SHAFT REAR COVER ADAPTER HOUSING al TRANSMISSION E E Fig 7 22 Installing governor assembly HT 750CRD HT 754CRD HT 750DRD center support Using lifting bracket J 24195 remove the center support 2 Remove the white color coded snapring Remove the second clutch plates Retain the plates in a pack 3 Attach lifting bracket J 24196 to the main shaft of the gear unit assembly Attach a hoist to the eyebolt on bracket J 24196 Lower the gear unit assembly as assembled in para 6 20 into the transmission housing engaging the internal splines to the rear carrier hub with the external splines of the output shaft 4 Install 13 pre selected second clutch plates beginning with an external tanged plate and alternately installing Wr tanged six internal splined plates fig 7 15 Be sure a E steel plate is next to the a to para 7 B 1 5 Install the white color coded that retains the second clutch plates
84. front planetary carrier assembly anchored against rotation by second clutch application the rotating center ring gear rotates the center sun gear shaft via the carrier pinions The center sun gear is integral with the sun g e a r shaft assembly to which the front sun gear is splined The rotating front sun gear rotates the f ront carrier pinions whose carrier is anchored against rotating by the applied second clutch In turn the rotating f r o n t carrier pinions rotate the front ring gear which along with the center carrier is splined to the r e a r planetary through the connecting drum Since the rear carrier hub is splined to the connecting drum on one end and to the low carrier ring gear on the other end rotation speed of all three components are the same With the low ring g e a r driving the low planetary pinions and the low sun gear which is splined to the rotating main shaft also driving the low pinions output shaft rotates at a speed reduction as shown in Copyright 1983 General Motors Corp 2 33 p LOCKUP CLUTCH TORQUE CONVERTER FOURTH CLUTCH A THIRD CLUTCH wie FORWARD etre CLUTCH f nu ae i insap IF esty FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON SECOND 4 N HT 740D HT 750D AUTOMATIC TRANSMISSIONS FIRST CLUTCH Low CLUTCH 2917 ps Dig LOW PISTON LOW PL
85. has its own circuit Each clutch except the forward clutch is connected to a relay valve and a trimmer valve The forward clutch is connected directly to the selector valve and does not connect to a trimmer valve It does not require connection to a trimmer valve because the vehicle is not moving 3 3 The first clutch circuit connects the clutch to the 1 2 relay valve and to the first trimmer valve In neutral the 1 2 relay valve is held upward by spring force and main pressure red is directed to the first clutch circuit The 1 2 relay valve cannot move downward unless the 1 2 signal line is charged This will not occur in neutral vehicle standing because there is no governor pressure to shift the 1 2 signal valve Only the first clutch is applied so the transmission output cannot rotate until two clutches are applied refer to fig 2 2 4 The first clutch in addition to being applied during neutral operation is applied also infirs t and reverse gears Shifting the selector valve from neutral N to drive 4 D4 or to any other forward drive range 3 2 or 1 charges the forward clutch circuit and applies the forward clutch The first clutch remains charged Application of the forward clutch a 1 s o directs main pressure through the priority valve to the 1 2 relay valve Shifting the selector valve from neutral to reverse R charges the fourth clutch while the first clutch remains applied In reverse fourth clutc
86. housing adapter Bolt 1 2 13 x 1 1 4 6 B Lockwasher 1 2 6 lb ft N m 15 20 20 27 67 80 91 108 FOLDOUI 23 HT 740D HT 750D Automatic Transmissions DNE dr n M t 4 hi gf RUN x 1 BW S N SK BN Y NN AT y Wr s A Foldout 23 Rear output disconnect clutch exploded view Copyright 1983 General Motors Corp 16387 B Foldout 23 2 p QA N I n is d rmn rmm LL a ge Front output disconnect clutch exploded view 16714A TM 5 4210 227 24 amp P By Order of the Secretary of the Army JOHN A WICKHAM JR General United States Army Chief of Staff Official R L DILWORTH Brigadier General United States Army The Adjutant General DISTRIBUTION To be distributed in accordance with Special List U S GOVERNMENT PRINTING OFFICE 1994 342 421 81886 TRAR ALONG PEREQRATEN HINE RECOMMENDED CHANGES TO EQUIPMENT TECHNICAL PUBLICATIONS SOMETHING WRONG WITH PUBLICATION FROM PRINT YOUR UNIT S COMPLETE ADDRESS THEN JOT DOWN THE DOPE ABOUT IT ON THIS FORM CAREFULLY TEAR IT OUT FOLD IT AND DROP IT IN THE MAIL D BD LBEEXACT PINPOINT WHERE IT S IN THIS SPACE TELL WHAT IS WRONG j AND WHAT SHOULD BE DONE ABOUT IT PRINTED NAME GRADE OR TITLE AND TELEPHONE NUMBER SIGN HERE DA FORM 2028 2 PREVIOUS EDITIONS P S IF YOUR OUTFIT WANTS TO KNOW A
87. hs TE BOR et Pi LT 1 2 13 X 2 424 WASHER 21 Sh o BO Fig 5 42 Removing rear cover retaining bolts HT 740D 747D Copyright 1983 General Motors Corp Fig 5 43 Removing rear cover HT 740D 747D NOTE Tie the first clutch plates together and identify the pack Retain for Inspection 4 Refer to paragraph 6 27 for rebuild of transmission housing 5 14 REMOVING REAR COMPONENTS HT 750CRD HT 754CRD a Governor A foldout 20 1 If the governor was not previously removed proceed as follows 2 Position the transmission rear upward 3 Remove four bolts 43 A foldout 20 4 Remove cover 42 and gasket 41 5 Rotate governor clockwise then remove it assembly 38 DISASSEMBLY OF TRANSMISSION MANEAT ANE IIT CIA STEAM a a Abe RT pP p Grit E S RU m SUME o eel qe e EET n 1 EESTI DOM DU M ERO a n 5s Fig 5 44 Removing rear cover bolts HT 750CRD HT 754CRD 6 Refer tolparagraph 6 31 for rebuild of the governor assembly b Rear Cover 1 Remove the twenty four bolts and washers that retain the rear cover and the adapter housing to the transmission housing fig 5 44 2 Attach a h o i s t to the lifting bracket fastened to output shaft and carefully separate the rear cover from the adapter housing fig 5 45 Remove the rear cover gasket 3 Refer to paragraph 6 26 for rebuild of the rear cove
88. i r RING GEAR 56 JU Fig 7 26 Installing first clutch plate HT 750DRD A nATTED ee Iac To ADAPIENR AHS N6G n ir ay Fig 7 27 Installing adapter housing HT 750DRD 2 Carefully place the adapter housing assembly as assembled in onto the transmission housing Since the dowel pins are different in size installation is simplified 3 Install four 1 8 inch cotter pins 1 1 2 inch max length into the four oil holes Copyright 1983 General Motors Corp 7 14 ASSEMBLY OF TRANSMISSION nearest the rear of the rear planetary ring gear Refer to figure 5 51 NOTE Figure 4 6lillustrates a handy tool that may be easily improvised Such a tool will ensure that the cotter pins will be removed before assembly is completed 4 Install gear and hub assembly 19 A foldout 19 larger end first into the rear planetary ring gear The hub will stop when it reaches the four cotter pins 5 Install bearing race 21 A foldout 18 flat side first onto the rear of gear and hub assembly 19 Coat needle roller bearing 22 and r a c e 23 with oil soluble grease and install it onto race 21 Install olanetay carrier assembl ias assembled into the adapter housing fg 7 28 with external tanged plate mm install seven external tanged and six internal splined low clutch plates fig 7 28 PLANETAR Y CARRIER ASSEMBLY 53031 Fig 7 28 Installing low clu
89. in the valve body and main housing for porosity broken lands cracks dirt and land surface imperfections These imperfections will cause severe oil leakage leading to transmission failure The oil tracks identified in figure 4 7 will assist in locating troubled areas f Inspecting Bearings 1 Inspect bearings for roughness of rotation Replace a bearing if its rotation is still rough after cleaning and oiling 2 Inspect bearings for scored pitted scratched cracked or chipped races and for excessive wear of rollers or balls If one of these defects is found replace the bearing 3 Inspect the defective bearing housing and shaft for grooved burred or galled conditions that would indicate the bearing had been turning in the bore or on the shaft If the damage cannot be repaired with crocus cloth replace the defective part 4 When installing a bearing on a shaft heat the bearing to 2000F 930C in an oil bath approximately 30 minutes Use the proper size installation sleeve and a press to seat the bearing 5 When removing a bearing do not apply pressure across the balls This can cause brinelling and bearing failure 6 bearing must be removed installed without a sleeve press only on the race which is adjacent to the mounting surface If a press is not available seat the bearing with a drift and hammer driving against the supported race g Inspecting Bushings Thrust Washers 1 Inspect bu
90. in this position This adjustment should allow switch to work during clutch pedal play before actual clutch disengaging takes place OFF ON DASH SWITCH INSTALLATION Standard for all In line 71 and 92 Series Detroit Diesel Engines 2 O Mount the dash switch In a convenient position for operation by the driver Install the wiring in the vehicle as shown in wiring diagram below NOTE Plastic ties are included in the Engine Brake kits and should be used to secure the wiring for a neat Installation If necessary cut the wire to the required length to eliminate bundling up of loose wire NOTE The switch contacts are protected against arcing by a small diode connected between the load side switch terminal and ground The Engine Brake must be connected to the load side terminal If the vehicle has a positive ground electrical system reverse the position of the diode DASA SWITCH TO KEY Sw TCH ud FUSE ON wr te fist SS 1494 CLUTCH SWITCH OFT BUFFER tie x sere e o M o A Mm M rn DIODE POS TION FOR NEGATIVE GROUND ENGINE BRAKE UNITS THREE POSITION DASH SWITCH INSTALLATION Standard for all 6V and 8V series 71 or 92 Detroit Diesel Engines This new three position switch provides the operator with two degrees of braking Install the wiring in the vehicle as
91. installed either first The hole in the front of the spindle must be toward the housing s center bore 240 30 from a vertical line Press the spindle forward until its rear end face is flush with the front of the housing s counter bore Install flat washer 18 lockwasher 19 and bolt 20 Tighten the bolt to 83 100 Ib ft 113 135 Nem 5 If lubrication valve pin 61 A foldout 11 valve 60 and spring 59 were removed install new parts Install valve 60 larger end first onto pin 59 Install spring 59 into its cavity in the housing Press the pin until its head is 0 30 inch 7 62 mm above the housing surface adjacent to the valve 6 Install four 1 8 inch plugs 36 foldout at the bottom of the housing ugs 36 A 6 32 Use sealant on the threads Tighten the plugs 4 5 Ib ft 5 4 to 6 7 Nem 7 Install the ground sleeve and retain it with eight 3 8 16 x 1 1 2 inch bolts fig 6 33 Tighten the bolts to 36 43 Ib ft 49 58 Nem 8 Position the housing front downward 6 32 Install the retarder plate gasket aligning its holes with those in the converter housing 9 Install the retarder plate fig 632 Retain the retarder plate with eighteen 3 8 16 x 1 inch bolts and one 3 8 16 x 1 1 2inch bolt Tighten the bolts to 36 43 Ib ft 49 58 Nem 10 Assemble a n d install the oil pump as outlined in paragraph 6 10b 15 through 21 Note that the oil pump includes two driven gears 11 While holding the oil pump in p
92. is retained to the bottom of the transmission housing with twenty three screw and washer assemblies 4 Most oil pans h a v e two holes One at the side to attach the oil filler tube The other hole is at the rear of the pan f o r convenient draining of t h e oil Earlier oil pans provided one hole for filling and draining the oil 5 Oil pans with three holes were designed to accommodate an oil preheating element or the shift assist feed line required on split shaft transmissions 6 Oil 33 foldout 16 29 29 B foldout 17 are boxlike sheet metal frame with a perforated sheet metal reinforcement covered by a fine mesh screen across the bottom Sump oil is drawn through the screen by the oil pump and directed into the hydraulic system The filters are retained to the bottom of the control valve with bolts NOTE The dropbox has its own oil system requires a different grade of oil b Function foldout 16 1 The oil pan holds the oil supply for the transmission and covers the control valve body assemblies and oil filter It does not hold the oil supply for the dropbox 2 The oil filter screens all oil entering the hydraulic system 2 26 REAR ADAPTER HOUSING a Adapter housing 9 Aj foldout 19 is machined to receive first clutch piston 6 Cast slots inside t h e housing receive the tangs of the external tanged clutch plates of the low clutch b b The rear adapter h
93. locking retainer ring 4 7 Spring retainer 8 Piston release spring 20 9 Third clutch piston 10 Piston inner sealring 11 Piston outer sealring 12 Butt joint sealring 2 13 Needle roller bearing 14 Thrust bearing race 15 Center support housing assembly 16 Bushing 17 Center support housing 18 Piston outer sealring 19 Piston inner sealring 20 Second clutch piston 21 Piston release spring t20 22 Spring retainer 23 Self locking retainer ring 4 24 Snapring 25 Internal splined clutch plate 6 26 External tanged clutch plate 7 0 0993 0 1063 THK Red AR 0 1161 0 1231 THK Green A 2 Sleeve assembly 28 Pin 29 Sleeve A Foldout 14 Fourth clutch assembly exploded view HT 740D HT 750D AUTOMATIC TRANSMISSIONS FOLDOUT 14 B Foldout 14 Third clutch center support and second clutch exploded view Copyright 1983 General Motors Corp A 1 Gear unit and main shaft assembly 2 Thrust washer 3 Front planetary sun gear 4 Crust washer 5 Front planetary carrier assembly 6 Flange and carrier assembly 7 Sleeve bushing 8 Bronze thrust washer 12 9 Needle roller bearing 6 10 Pinion 6 11 Steel thrust washer 12 12 Pinion pin 6 13 Thrust washer 14 Snapring 15 Front planetary ring gear 16 Center planetary carrier assembly 17 Pinion pin 4 18 Center planetary carrier 19 Bronze thrust wa
94. locknut as viewed from fuel rack side of cylinder head and rotate rocker lever to provide approximately 1 16 16 mm more valve lash This clearance is obtained to accommodate the thickness of the Jacobs valve stem when installed cb Si aia 2 Valve On engines ponia with high mount injector clamps remove clamp by removing bolt and special washer Replace with Jacobs high mount clamp and the same washer and bolt IMPORTANT Tighten bolt to 20 25 Ib ft 27 34 N m The Jacobs clamp can be identified by a small milled section on one side This provides clearance for the exhaust valve stem cap _ 2 Valve Install Jacobs ee oes caps on right hand exhaust valves one per cylinder Press caps firmly over valve springs Hexagon cover studs must be removed if located near this valve MH t n 2 Valve Using thie clamping tool from the Jacobs Kit back off thumb screw Install tool squarely over valve stem cap with Its feet under the exposed coil of valve spring Tighten thumb screw to seat cap Remove Tool Replace rocker shafts and pedestals 2 Valve If a spam cover stud is located near a right hand exhaust valve replace It with a round Jacobs cover stud which provides the necessary cap clearance Use iin BEN Luiz uei in Riesa to stud Assemble Jacobs lent Hand iul pipes m 1 Tx ra xd LE 2 a m et at z gr os z
95. longer the interval between clutch plate replacements will be Replace worn plates with new plates to establish 7 the desired clearance If the assembly is satisfactory FOURTH CLUTCH continue assembly withb below Tee Em 5 If the clearance is not satisfactory replae Me j the plates in the third clutch as required to obtain a A CC s A satisfactory clearance Refer T C MOT wear limits in Section 8 Ac SW 6 Prior to the installation of the fourth clutch assembly be sure the bearing races at both the front and back are in place tio 6 46 landl 47 Check also that the sealrings bearing and race are in place on the center support 47 P k boat if iat Fig 7 33 Installing third clutch snapring NOTE Do not remove the support ring from the fourth clutch housing 7 Place lifting bracket J 24209 under the spring retainer of the fourth clutch Copyright 1983 General Motors Corp 7 18 ASSEMBLY OF TRANSMISSION assembly refer to fig 5 35 Align the internal splines of the third clutch plates and the sun gear shaft to the fourth clutch housing Install the housing 8 Be sure the bearing race at the top front of the clutch is in place If not lubricate it with oil soluble grease and install b Forward Clutch WARNING Be sure the forward clutch hub and the fourth clutch driving hub are installed into the forward clutch assembly as
96. method is used to select second clutch components disregard 1 following 1 Install thirteen second clutch plates beginning with an external tanged plate Alternately install seven external tanged plates and six internal splined plates fig 7 3 Retain the plates with selective snapring 155 157 f Tad The snapring must be color d dh Be sure the snapring gap is at the top of the transmission housing regardless of its position when removed 3 Remove the third clutch piston from the center support assembly if not previously removed Install bracket J 24195 into the recess between the sealrings on the center support hub fig 7 5 4 meta the center support into the transmission housing Be sure the tapped hole in the support is a with the anchor bolt hole in the bottom of the housing 5 Remove lifting bracket J 24195 from the center support Install a used 3 8 16 x 2 1 4 inch anchor bolt into the support through the anchor bolt hole in the bottom of the housing WEZ Tighten the bolt finger tight 6 Place the compressor sleeve J 24208 2 on the hub of the center support Place compressor J 24208 3 across the transmission housing Retain the compressor bar with two bolts fig 7 6 7 Compress the center support by applying a torque of 5 Ib ft 6 78 Mm to the center screw J 24208 1 Determine the width of the snapring opening using gage J 24208 13 or 15 fig 7 6 The lugs of the gage are color cod
97. modulator pressure will cause a downshift if governor pressure alone will not hold the valve upward 4 At the trimmer regulator valve modulator pressure assists in regulating the trimmer regulator pressure against t h e spring at the top of the valve 5 At the lockup valve modulator pressure causes lockup to occur at a lower vehicle speed IN Trimmer Regulator Valve 1 The trimmer regulator valve reduces main pressure to a regulated pressure The regulated pressure is raised or lowered by changes in modulator pressure red and green 2 Trimmer regulator pressure is directed to the lower side s of the trimmer regulator plug s tov ar y the clutch apply pressure pattern of the trimmer valves A higher modulator pressure closed throttle Copyright 1983 General Motors Corp 2 17 HT 740D HT 750D AUTOMATIC TRANSMISSIONS will reduce trimmer regulator pressure This results in lower initial clutch pressure Conversely a lower modulator pressure open throttle results in higher regulator pressure and a higher initial clutch pressure j Trimmer Valves 1 T h e purpose of t h e trimmer valves is to avoid shift shock The valves reduce pressure in the clutch apply circuit during initial clutch application then gradually return the pressure to the operating maximum This applies the clutch gently to prevent harsh shifts 2 Although each trimmer valve is calibrated for the clutch it serves all trimmers function
98. needle bearing NOTE If the disconnect shaft is not permitted to stroke to the full disconnect position the driven gear may move far enough to disengage the driving gear but not enough to allow sufficient oil to reach the needle bearing for adequate lubrication The bearing will fail 1 If a manual or a i r actuator is used adjust the linkage or the cylinder stroke to give a crisp detent at the engaged and disengaged positions 2 Push the shifter shaft inward to the engaged position detent Rotate the shaft until the outer end of the shaft is 1 29 to 1 33 inches 32 8 to 33 8 mm from the face of the housing 3 10 SHIFT SPEED ADJUSTMENTS NOTE Transmission shift points cannot be satisfactorily adjusted if the transmission has the J wrong governor installed Check the three digit code on the head of the governor with the code shown in the current parts catalog SA 1268 for the governor listed for your transmission assembly part number If the letter M follows the three digit code the governor is a service replacement assembly If the M is not included the governor was installed at original factory build a Calibrated On Test Stand Or In Vehicle 1 Proper timing of shift speed points is necessary for maximum transmission performance Shifts may be adjusted on the test stand when the transmission is rebuilt or overhauled or during road testing of the vehicle Copyright 1983 General Motors Corp 3 8
99. of transmission On later transmissions the snapring is not beveled Be sure the proper snapring is used and that it is fully expanded into the groove 3 Pack the rear oil seal with high temperature grease that conforms to MIL G 3545A Place the seal on oil seal installer J 24202 1 sealing lip facing installer Attach handle J 24202 4 Apply a non hardening sealer Perfect Sealer No 4 or equivalent onto the outer surface of the rear oil seal Pre coated seals do not require sealer on the O D 4 Insert the seal installer and the seal into the rear cover and drive the seal into the bore until its rearward surface is 0 60 to 0 70 inch 15 2 to 17 8 mm in front of the parking brake mounting surface plane 5 Coat the outer circumference of the dust shield with non hardening sealer Install the shield flat side first into the rear cover Press the shield flush to 0 04 inch 1 02 mm below the surface 6 Install the output flange and retainer nut per paragraph 3 144 Install the speedometer driven gear into the cover 3 16 REPLACING MANUAL DISCONNECT OUTPUT SEAL a Remove Seal 1 Disconnect the equipment drive shaft from the output flange 2 Remove the two bolts lockstrip and shims that secure the flange retainer to the output shaft Remove the flange retainer 3 Using a puller remove the output flange 4 Using seal remover J 24171 1 2 and 4 remove the oil seal from the disconnect housing b Insta
100. path HT 740D HT 747D g Fourth Gear Operation fig 2 6 Engine torque is transmitted through the lockup clutch as described in b above The forward and fourth clutches are applied With the clutches applied the transmission main shaft and the sun gear shaft are locked together and rotate as uni at input speed With the center and rear sun gears rotating at the same speed locked together and their carriers splined to the planetary connecting drum all components rotate at input speed The transmission output shaft is splined to the rear carrier and thus produces an output ratio of 1 00 1 Copyright 1983 General Motors Corp 2 28 T FORWARD TORQUE THIRD DESCRIPTION AND OPERATION m FRONT CLUTCH CONVERTER dutch PLANETARY CENTER CENTE m TURBINE PLANETARY aui SHAFT X Foumm p fetu Ze if f St m m MAIN SHAFT SUN GEAR SHAFT CONNECTING ipa c FIRST CLUTCH FA 8 pet aeg D Une M S 000 UTP ee Ea SHAFT REAR SUN GEAR Vn PLANETARY CLUTCH APPLIED DRUM 01 TORQUE PATH Fig 2 7 Reverse gear torque path HT 740D HT 747D h Reverse X Gear Operation Itig 2 7 Engine torque is transmitted through the torque converter as described in a above Reverse gear is the only gear in which the forward clutch is not engaged In this gear the fourth clutch is applied and this rotate
101. produces second gear when the forward and second clutches are applied fig 2 4 2 The center planetary is active in second third fourth and reverse gears but only in second and reverse gears is the compounding of two planets required Copyright 1983 General Motors Corp 2 9 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 3 Therear planetary carrier assembly 39 A foldout 15 is active in first and reverse gears In first gear t h e rear planetary acts alone to transmit torque to the transmission output shaft via main shaft 36 sun gear 37 and four pinions in carrier assembly 39 Reverse gear is activated by compounding the center and rear planetary carriers NOTE In fourth gear because both the forward and fourth clutches are engaged all three planetaries rotate as a unit This gives direct drive through the transmission 2 17 PLANETARY GEARING HT 750CRD HT 754CRD a Description foldout 15 1 Ihe planetary gearing is composed of a gear unit and main shaft assembly 1 Bj foldout 15 the low planetary carrier assembly 18 Bj foldout 18 and its sun gear and ring gear 2 The gear unit and main shaft assembly itur contains three planetaries called front center and rear so designated because of their location in relation to each other in the gear unit 3 Each of the three planetaries has a sun gear and a ring gear which are interconnected by the main transmission shaft and a connecting drum 4
102. retaining bar J 24208 3 adapter housing and gasket fig 5 49 Remove the bar housing and gasket 11 Refer td paragraph 6 27 for rebuild of the transmission housing 5 16 REMOVING REAR COMPONENTS 750DRD a Governor B foldout 19 1 If the governor assembly was not previously removed proceed as follows 2 Position the rear end upward 3 Remove four bolts 31 Bj foldout 19 4 Remove cover30 and gasket 28 b Rotate governor assembly clockwise then remove it 6 Refer paragraph 6 31 for rebuild of the governor assembly b Rear Cover HT 26 NOTE The procedure in 1 below follows the removal of the second clutch 5 12c Position the transmission front upward The improvised tool shown in figure 4 3 may be used or cotter pins alone fig 5 49 1 Locate the oil passage holes in the rear planetary ring gear Insert four 1 8 inch cotter pins ninety degrees apart into the oil passage holes in the ring gear until they bottom Gig 5 501 The pins should be greased to retain them and should be in holes in the same plane 2 Carefully invert the transmission housing rear cover upward Remove the twenty four bolts and washers that retain the rear cover and adapter housing to the transmission housing fig 5 44 ON HOUSTNCS SEM Fig 5 50 Retaining low sun gear and hub assembly HT 750DRD Copyright 1983 General Motors Corp 5 22 DISASSEMBLY OF TRANSMISSION
103. sade T T Le n i x pen IMPORTANT Torque fuel pipe nuts to 12 to 15 Ib ft 16 20 Nem NOTE This torque specification is very important and should be strictly adhered to Over tightening or under tightening may cause fuel pipe failure and engine lube oil dilution Serious engine damage may result Be careful not to contact the fuel pipe with the fuel pipe nut wrench as this may cause damage to the flare BRAKE ARRANGEMENT FOR 4 V 8 amp V 16 E Y in Y i Y E Y er BRAKE ARRANGEMENT FOR 6 amp V 12 Prior to installing units on engine Brake housings should be laid out on work bench in order shown in diagram to match engine configuration Jumper and seal rings X should be Inserted into each unit as indicated in diagram oll jumper Win lock nut attached Screw In approximately 1 2 inch 12 7 mm to avoid damage in assembly to engine Insert and tighten 5 16 24 plugs on outboard side of calls Brake Units EN ies i ERE insert lube seal r ring a E das k XIBCODS hold TETTE me Screws to brake housing Position housing over rocker and pedestal assembly insuring the master piston fork guide assembly is properly located over the injector push rod clevis Torque hold down cap screws to 88 92 Ib ft 119 125Nem CAUTION Make certain that fuel pipes do not interfere with the Engine Brake Housing A fuel pipe rubbing on the Engine Brake Housing will cause failure o
104. shifting is accomplished in all ranges on the HT 740D HT 747D HT 750CRD an d HT 754CRD transmissions The HT 750DRD HT 750DRD DB transmissions must be manually shifted into and out of first range while the remaining ranges are automatic Design incorporates four speeds forward and one reverse on the HT 740 models and five speeds forward and one reverse on the HT 750 models All transmissions were designed for operation with a diesel engine b Torque Converter A simple 3 element torque Ponce Ir EOS power from the engine to the transmission gearing The torque converter serves as both a fluid coupling and a torque multiplier Five combinations of torque converter elements may be used These give converter stall ratios of 3 04 1 2 21 1 2 70 1 2 56 1 2 09 1 and 1 83 1 Lockup Clutch This clutch automatically locks the turbine element of the torque converter to the flywheel When the turbine approaches the speed of the pump hydraulic pressure automatically applies the lockup clutch With the lockup clutch applied engine output is directed to the transmission gearing at a 1 1 speed ratio A decrease in speed automatically releases the lockup clutch d Hydraulic Retarder 1 The hydraulic retarder contains a turbine driven paddle type rotor enclosed by two vaned castings The retarder plate assembly 2 or 19 B foldout 12 is located on the front side of the rotor and the retarder housing 16 on the rear 2
105. shown in figure 6 45 If these two hubs are installed into the third clutch housing by mistake the transmission will operate in reverse when the driver selects any forward range 1 Prior to installation of the forward clutch assembly make sure the thrust bearing race and thrust bearing have been installed at the rear of the clutch assembly Install thrust race 2 B foldout 13 cup side first onto the forward clutch hub Install needle bearing 24 A foldout 13 onto the race Refer to foldout 1 Retain the bearing and race with oil soluble grease 2 Install alignment fixture J 24221 Engage the fourth clutch plates by applying air pressure to the fourth clutch piston fig 7 34 If all plates do not engage tool J 24221 the fixture will rise slightly when air pressure is applied 3 Hold air pressure in the clutch and remove the fixture Continue holding air pressure and install the forward clutch assembly with race and bearing fig 7 35 4 Release the air pressure when the forward clutch is fully seated forward clutch will fall slightly when air is released if the clutch is not fully seated LN q pes ruipn PCHITPE p ATES mo Fig 7 34 Applying air pressure to fourth clutch piston 5 Make sure the thrust bearing race on the front of the forward clutch assembly is installed fig 7 36 If not apply oil soluble grease to the race and install it 6 Be sure to install a new center suppor
106. the established normal value When deviations do not exceed 150 rpm and can be attributed to such causes the actual speed can be accepted as normal 2 After making allowances for items in Note above a low engine speed may indicate the engine is not delivering full power Refer to the engine service manual for engine repair information 3 If low engine speed persists after the engine is tuned refer to the troubleshooting chart in paragraph 3 20 4 If high engine speed is noted refer to the troubleshooting chart in paragraph 3 20 3 13 PRESERVATION AND STORAGE a Storage New Transmissions prior to installation New transmissions are tested with preservative oil and drained prior to shipment The residual oil remaining in the transmission Copyright 1983 General Motors Corp 3 13 HT 740D HT 750D AUTOMATIC TRANSMISSIONS provides adequate protection to safely store the transmission for one full year stored without further treatment inside in conditions of normal climate and with all shipping plugs installed b Preservation Methods When the transmission is to be stored or to remain inactive for an extended period one or more years specific preservation methods are recommended to prevent damage due to r u s t corrosion and organic growth in the oil Preservation methods are presented for storage with and without transmission fluid c Storage One Year Without Oil 1 Drain the oil 2 Seal
107. the area to remove the defect is not necessary or desirable If the defects are too severe replace the defective part 2 At locations contacted by springloaded lip type seals inspect for n i c k s scratches roughness or other surface irregularities Also inspect for embedded particles step wear and dirt on flanges or any other components exposed to external contamination Remove the defects and restore the finish Replace the part if scores or scratches would permit oil leakage 4 6 ASSEMBLY PROCEDURES a Clutches Pistons 1 After clutch pack clearances have been established soak each friction face clutch plate 2 minute minimum in transmission fluid prior to final assembly 2 Apply generous amount of transmission fluid to the piston cavity prior to final assembly 3 Assemble clutch plates so that the cone of each plate faces the same direction as the cone of the adjacent plates b Parts Lubrication During final assembly lubricate all moving parts with transmission fluid The lubricant will help protect the friction surfaces and ferrous metals until the unit is in service Threaded Plugs Hydraulic Fittings 1 New precoated plugs New plugs that are precoated with Teflon need no preparation for assembly 2 Reused or uncoated plugs hydraulic fittings Prepare the threads with a small amount of nonhardening sealer such as Loctite Pipe Sealant with Teflon or equivalent Do not use Teflon
108. the gear from the housing 20 To compress the snapring insert 10 pieces of steel shim stock 3 32 x 0 020 x 3 between the snapring and the PTO gear To accomplish this locate the snapring gap and at the cut out nearest the gap press the snapring into the groove in the housing Slip a piece of shim stock between the snapring and the inner ends of the splines of the PTO gear Repeat the operation at the other side of the snapring gap Working at each opening missing spline to compress the snapring insert the remaining pieces of shim stock at approximately 3 inch increments TA Fos eT 2 4 M eM faia STEEI M i nid D STO A XR D ow p met x24 za o I 11 AN M tee qe eo ro ru JE LUMINE Cu Pipe 22 1 RAIN 4 53750 Fig 6 39 Removing gear from forward clutch 21 Slide the gear free of the clutch housing Remove the snapring CAUTION Do not damage oil collector ring during PTO gear removal 22 On later models the PTO gear is press fitted on the clutch housing 23 Remove oil collector ring 6 B foldout 13 from clutch housing 5 by supporting the inner circumference of the ring and pressing the forward clutch housing and input shaft assembly free 24 Place PTO gear fixture J 26899 2 on a press flat side downward Repeat items 19 and 20 above 25 Position the clutch housing turbine shaft d
109. to the converter in circuit escapes to the sump through the converter bypass valve and secondary converter pressure regulator valve f Selector Valve Forward Regulator Circuits foldouts 5 6 7 8 1 The selector valve is manually shifted to select the operating range desired The HT 740D or HI 747D m od e 1 can be shifted into six lever positions R reverse N neutral D4 drive 4 D3 drive 3 D2 drive 2 D1 drive 1 2 The HT 750 model can be shifted into seven lever positions R reverse N neutral D5 drive 5 D4 drive 4 D3 drive 3 D2 drive 2 D1 drive 1 At each of these positions the selector valve establishes the hydraulic circuit for operation in the condition indicated NOTE The quadrant designations listed above are n o t necessarily the same as those in the vehicle 3 On model HT 7400 HT 747D foldout 5 drive 1 drive 2 drive 3 and drive 4 are forward ranges Anytime the vehicle moves forward regardless of what range was selected the transmission starts in first gear except 2nd gear start units Shifting is automatic in any of the above ranges varying with vehicle speed and throttle position 4 Second g e a r start units utilize automatic forward motion in second third and fourth gears HT 740 747D or second third fourth and fifth gears HT 750 First gear must be manually selected and will not automatically shift to the next higher gear unless maximum governor p
110. top of the 1 2 relay valve foldout 7 Hydraulic fluid holds the 1 2 shift valve down until governor pressure charges the line refer Hydraulic fluid foldout 7 forces the relay valve down against its spring allowing main pressure to apply low clutch refer para 2 31p 6 2 23 LOCKUP CUTOFF VALVES a Description A foldout 21 1 The lockup valve body assembly 28 contains three identical valves 33 36 and 37 The assembly is bolted to the lower front of the oil transfer plate in the transmission oil pan 2 The valves move in their bores in response to various clutch pressures at the moment the clutches applied Some transmission assemblies do not include lockup cutoff valves b Operation 7400 747D foldout 5 1 When either the first second third or fourth clutch is applied pressure is sent to the lockup cutoff valves In first gear a valve is pushed upward and pressure can then charge the lockup feed line Lockup will occur in first gear when front governor pressure is sufficiently high Lockup will not occur in first gear on models equipped with rear governor option 2 When the transmission shifts to second gear first clutch pressure is exhausted and the lockup clutch if engaged releases Also second clutch pressure is exerted upon the opposite end of the same valve from which first clutch pressure was released However second clutch pressure must initially flow through an orifice to move the
111. two members of the low planetary system are driving members rotating at differing speeds the third member carrier becomes the output member This in turn drives the output shaft at a speed reduction shown in paragraph 1 6 Copyright 1983 General Motors Corp 2 32 DESCRIPTION AND OPERATION LOCKUP CLUTCH TORQUE CONVERTER FOURTH CLUTCH FORWARD ierre n Se i Eu L3 FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON 77 THIRD CLUTICHS SECOND HH P FIRST CLUTCH LOW CLUTCH E Lum LBS E VLE Ow PISTON i LOW PLANETARY CARRIER LL FIRST CLUTCH PISTON REAR PLANETARY CARRIER CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON Ez CLUTCH APPLIED f TORQUE PATH JA S2962 Fig 2 11 Third gear torque path HT 750CRD HT 754CRD f Third Gear Operation 2 11 Engine t orque is transmitted through the torque converter as described in a above The forward and the second clutches are applied T h e second clutch application anchors the carrier of the front planetary assembly against rotation The forward clutch application locks the turbine driven shaft input shaft and the main shaft together so they rotate as a unit The rear sun gear is splined to both the rotating main shaft and the center ring gear and all three parts rotate at input speed With the carrier of the
112. type Dexron auxiliary preheat required to raise temperature in sump and external cir cuit Transfer gear housing OI CAD ACY t 2 6 U S qts 2 5 liters Sao ee ee wn ee ee ere ee ee ere ree 30 weight C3 clo pee Integral separate from transmission HT 750CRD amp HT 750DRD amp HT 740D HT 754CRD HT 750DRD DB Oil pressure Main pressure dle 600 rpm in fwd or 90 psi 90 psi 90 psi 621 kPa min 621 621 Stall 1200 RPM in fwd 140 175 psi 140 175 psi 235 270 psi 965 1206 kPa 965 1206 kPa 1620 1861 kPa Stall 1200 RPM in rev 235 270 psi 235 270 psi 235 270 psi 1620 1861 kPa 1620 1861 kPa 1620 1861 kPa 1500 2000 RPM in all 140 175 psi 140 175 psi fwd ranges 965 1206 kPa 965 1206 kPa 4th and 5th 140 175 psi 965 1206 1st converter 2nd 235 270 psi converter and rev 1620 1861 kPa dd 1st lockup 2nd lockup 140 175 psi rev lockup 965 1206 kPa LOCKUP pressure essessseseeenenen nennen nnnm nnn nnns Must be within 10 psi 69 kPa of main pressure Dexron is a registered trademark of General Motors Units incorporating all range lockup Copyright 1983 General Motors Corp 1 10 GENERAL INFORMATION SPECIFICATIONS AND DATA CHART cont Lubrication pressure Hetarder mode
113. valve downward This delays the movement of the valve to a point where second clutch pressure can again apply the lockup clutch 3 Similar actions occur at the other two valves when second clutch pressure is released and third clutch pressure is applied and when third clutch pressure is released and fourth clutch pressure applied 4 The delay in valve movement provides a momentary release of the lockup clutch between upshifts In downshifts similar actions occur but in a reverse sequence Copyright 1983 General Motors Corp 2 12 DESCRIPTION AND OPERATION c Operation HT 750DRD foldouts 7 8 1 Operation of t h e lockup cutoff valves in the HI 750 model is similar to that described for the HT 740 In some models the f i r s t through fourth clutch pressures provide lockup feed for second through fifth gears respectively T here is no lockup in first gear foldout 7 2 In HT 750DRD models foldout 8 low clutch pressure is brought into the same valve that receives second clutch pressure through a shuttle b a 1 1 check valve Thus lockup is effective in all gears 2 24 SECOND GEAR START HT 740 HT 747 HT 750CRD HT 754CRD a Description The second gear start feature provides vehicles equipped with a 3 19 1 or 3 69 1 first gear ratio an option of automatically bypassing first gear and accelerating the vehicle in second gear from a standing start b Forward Gear Operation vehicle stationary Shif
114. very little clearance It may bind in the housing if the housing is cold Heat the housing slightly if necessary Do not use a torch to heat the housing A heat lamp or a current of warm air is sufficient If the support assembly starts upward and then binds tap it downward and lift again 4 Lift carefully straight upward on the lifting bracket to remove the center support assembly If the thrust washer adheres to the rear of the support remove it b Refer to paragraph 6 19 for rebuild of the center support assembly b Gear Unit 1 Attach lifting bracket J 24196 to the main shaft of the gear unit assembly fig 5 40 Copyright 1983 General Motors Corp 5 16 DISASSEMBLY OF TRANSMISSION CENTER SUPPORT 7 ANCHOR BOLT LE ee 52980 Fig 5 38 Removing center support snapring 2 Attach a hoist to the lifting bracket eyebolt and remove the gear unit and shaft assembly from the transmission housing fig 5 40 3 In HT 750DRD model remove race 16 A hasard needle bearing 17 and race 18 from gear and hub assembly 19 one or both of these items might adhere to the gear unit when removed Fig 5 40 Removing gear unit assembly HT 740D 747D or HT 750DRD Copyright 1983 General Motors Corp 5 17 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 4 Refer to paragraph 6 20 for rebuild of the HT 740D 747D gear unit or to 6 21 for HT 750DRD c Second Clutch 1 Rem
115. was prepared for storage without oil drain the residual oil and replace the oil filter elements Refill the transmission to the proper level with Dexron or Dexron II transmission fluid 5 If the transmission was prepared for storage with oil it is not necessary to drain and refill the transmission with new transmission fluid Check for proper fluid level para 3 3 Add or drain transmission fluid as required to obtain the proper level Hemove all tape from openings and the Wash off all external grease with mineral 3 14 RETAINING OUTPUT FLANGE a Before removing the retaining nut check the number of notches that have been cut into the wrenching flats If there are five notches remove the nut and throw it away b If there are less than five notches or none at all remove all dirt and any burrs from the exposed shaft threads Then only loosen the nut until there is approximately 1 16 inch 1 59 mm gap between the nut and flange c Check the running torque while removing the nut The nut can be reused only if it meets the following requirements The first time no notches the nut is removed the running torque must be at least 400 Ib 45 N m Each additional time one to four notches the nut is removed the running torque must be at least 300 Ib in 34 N m d Each time the nut is reused deeply scri6e one of the wrenching flats This method of marking the nut will indicate how many times the nut has
116. 0 HT 750D AUTOMATIC TRANSMISSIONS A Foldout 10 Lockup clutch and torque converter exploded view 2854C B Foldout 10 Oil pump and converter housing for models without retarder or PTO exploded view 1 Sealring 2 Sealring 3 Lockup clutch piston 4 Lockup clutch plate 5 Lockup clutch back plate 6 Ball bearing 7 Key 8 Torque converter turbine assembly 9 Lockup clutch hub 10 Turbine hub 11 Turbine 12 Rivet 16 13 Torque converter stator assembly 14 Stator thrust washer 15 Stator cam washer 2 16 Stator 17 Stator cam 18 Freewheel side washer 19 Rivet 1 4 x 2 5 8 10 20 Stator freewheel roller spring 10 21 Stator Freewheel roller 10 22 Thrust bearing race 23 Thrust bearing 24 Stator freewheel roller race 25 External snapping 26 Converter pump spacer 27 Bolt 3 8 24 x 1 1 4 12 A Bolt 3 8 24 x 1 3 8 split bearing A 28 Lockstrip 6 29 Bearing retainer 2 earlier models 30 Bearing retainer later models 31 Sealring 32 Torque converter pump assembly 33 Torque converter pump 34 Balance weight AR 35 Balance weight screw AR 36 Ball bearing later models split race 37 Ball bearing earlier models 38 Double roll ball bearing with PTO 39 Power takeoff drive gear with PTO 40 Converter pump hub gasket later models 41 Converter pump hub gasket earlier models 42 Converter pump hub 43 Hook type sealring 44
117. 1 USE PLATE FOR SPECIFIC MODEL 4 6834488 3 6834762 1 DIM X PLATE PLATE FROM 6834488 6834720 3 0551 3 0418 ADD 1 REMOVE 1 PCS 3 0418 3 0098 3 0098 2 9965 REMOVE 1 ADD 1 2 9965 2 9878 REMOVE 2 ADD 2 Fig 6 112 Third clutch stack dimension Copyright 1983 General Motors Corp 6 68 Section 7 ASSEMBLY OF TRANSMISSION 7 1 SCOPE a This section covers the assembly of the HT 740D HT 747D HT 750CRD HT 754CRD HT 750DRD and HT 750DRD DB transmissions The assembly sequence is continuous and includes all models Where procedures apply to specific models they will be so identified b When a procedure does not apply to the specific model being assembled go to the next procedure which is applicable C Certain illustrations will not always illustrate the model being assembled but when the operation is identical the illustration will correctly illustrate the procedure NOTE The clearances for low first second and third clutches are established by direct measurement in this section para 7 3 para 7 3 7 11 Refer to paragraph 6 33 for stack dimension compun of clutch clearances 7 2 CLUTCH CLEARANCES a Preparation Procedure Preparations are required to establish the proper clearance for each clutch pack Follow the procedures in b below b Determine Plate Thickness 1 Determine the original thickness of each external tanged plate with a micrometer Because
118. 1 Om e L T No me 22 23 24 25 26 27 29 30 31 32 33 34 35 36 37 38 39 40 41 42 13 14 15 16 17 18 19 20 21 22 24 Retainer Locking strip Bolt 1 2 20 x 1 1 4 2 B Bolt 1 2 13 x 1 1 2 6 Lockwasher 1 2 6 Disconnect clutch housing adapter Lockwasher 1 2 6 Bolt 1 2 13 x 1 1 4 6 A Disconnect clutch housing gasket Output drive gear External snapring Output drive gear Shifter fork Disconnect clutch housing Lockwasher 1 2 2 Bolt 1 2 13 x 2 1 2 2 A Oil seal Rod wiper seal Shifter fork shaft Bolt 1 2 13 x 1 1 2 4 A Lockwasher 1 2 4 Detent sprin Detent ball External snaprin Shifter fork sha Rod wiper seal Oil seal Disconnect clutch housing Bolt 1 2 13 x 1 1 2 4 B Lock washer 1 2 4 Bolt 1 2 13 x 2 1 2 2 B Lockwasher 1 2 2 Shifter fork 43 44 45 46 47 48 49 90 51 92 93 94 99 56 97 Torque A B 26 A24 28 29 30 rol T Torque External snapring Output shaft Detent sprin Detent ball 6 Bearing retainer gasket Single row ball bearing Bearing retainer Lockwasher 1 2 6 Bolt 1 2 13 x 1 1 2 6 A Oil seal in Shim 0 025 Shim 0 005 4 Retainer Locking strip Bolt 1 2 20 x 1 1 4 2 B b ft Nem 67 80 91 108 15 20 20 27 Output drive gear External snapring Output drive gear Disconnect clutch housing gasket Disconnect clutch
119. 1 If removed install new dowel pins 11 and 12 into housing 10 They must project 0 360 to 0 400 9 14 to 10 16 mm above the front face of the adapter housing Install orifice plug 13 if removed flush with or to 0 060 inch below the front face of the housing 2 Place piston 6 in the piston cavity of housing 10 Be sure it is firmly bottomed in the cavity S recesses in the piston tangs are upward onto Install twenty eight springs 5 into their Install retainer 4 so the offset SPRING E28 2956 Fig 6 70 Removing retainer rings from first clutch piston HT 750 Copyright 1983 General Motors Corp 6 50 REBUILD OF SUBASSEMBLIES the piston and springs Align the holes in the tangs with the bosses on the piston 4 Using installerJ 24453 fig 6 56 install four retainer rings 3 B foldout 18 Press each ring into place until the adjacent retainer t a n g bottoms in the counterbore of the adapter housing CAUTION Failure to install the retainer rings properly can result in transmission damage or malfunction If installed too far onto the risers proper clutch clearance cannot be obtained If not installed far enough the retainers may fall off 5 When all four retainer rings are properly installed remove the piston assembly from the adapter housing 6 Lubricate sealrings 7 and 8 with transmission fluid Install the sealrings with the lip of each sealring facing rearward away from the spring s
120. 1 1 2inch bolts and three 3 8 16 x 2 1 2 inch bolts Tighten the bolts to 36 43 Ib ft 49 58 Nem b Refer to para 6 10b 15 through 21 for assembly and installation of the oil pump components 6 While holding the oil pump in position install six 3 8 16 x 5 inch bolts replacing guide bolts with last two Tighten the bolts to 36 43 Ib ft 49 58 Nem 7 Install the bearing race flat side first onto the front support hub Install the needle thrust bearing NOTE Grease both race and bearing with oil soluble grease to retain them 6 14 SCAVENGE OIL PUMP PTO IDLER GEAR a Disassembly A foldout 12 1 Place scavenge oil pump assembly 4 on the assembly table with external drive gear 5 down and remove snaprings 15 2 Remove oil scavenge pump body plate 13 3 Remove snapring 12 from the shaft of drive gear 5 4 Remove driven gear assembly 16 from spindle 10 b Remove drive gear 11 from the shaft of drive gear 5 Remove lock roller 6 from the shaft of gear 5 6 Remove gear 5 from pump body 9 7 If replacement is necessary press needle bearing 7 out of body 9 Press needle bearing 14 out of plate 13 8 If replacement is necessary spindles 10 toward the inside of body 9 9 Remove snapring 22 from both sides of gear 25 10 Remove bearing 23 or 34 from PTO idler gear 25 or 32 if replacement is necessary press Copyright 1983 General Motors Corp 6 25 HT 740D HT 750D SERIES TRAN
121. 10 7 2 to 8 8 1 85 17 3 38 6 28 0 32 0 to 39 1 8 10 Copyright 1983 General Motors Corp WEAR LIMITS AND SPRING DATA Table 8 2 SPRING DATA cont Spring Free Fold Color No Wire dia OD Length Length Under Load out Ref Spring Part No Code Coils 1n mm 1n mm 1n mm 1n mm 16 N 20 B 58 1 2 relay valve 6834528 oolid blue 11 0 073 0 680 1 52 1 10 7 2 to 8 8 yellow stripe 1 85 17 3 38 6 28 0 32 0 to 39 1 20 B 63 Governor accumulator 6836784 Solid yellow 13 0 041 0 400 1 90 1 15 5 93 to 6 17 valve 1 04 10 2 48 3 29 2 26 4 to 27 4 6838988 oolid orange 10 0 051 0 564 1 84 0 70 9 6 to 10 6 blue stripe 1 30 14 3 46 7 17 8 42 7 to 47 2 68 Priority valve 6835729 Solid white 11 0 054 0 384 1 17 0 94 8 15 to 9 25 yellow stripe 1 37 9 8 29 7 23 9 36 3 to 41 2 20 B 71 Hold regulator valve 6835733 Solid white 11 0 041 0 400 1 77 1 15 5 85 to 6 45 orange stripe 1 04 10 2 45 0 29 3 26 0 to 28 7 6836783 Solid orange 11 0 041 0 400 1 70 1 15 5 29 to 5 51 blue stripe 1 04 10 2 43 2 29 2 23 5 to 24 5 6836784 Solid yellow 13 0 041 0 400 1 90 1 15 5 93 to 6 17 1 04 1 T8 48 3 29 2 26 4 to 27 5 6836785 Solid white 14 0 041 0 400 2 01 1 15 6 22 to 6 48 1 04 10 2 51 1 29 2 27 7 to 28 8 6836867 Solid yellow 11 0 041 0 400 1 62 1 15 4 55 to 4 75 orange stripe 1 04 10 2 41 2 29 2 20 2 to 21 2 6836917 Black stripe 11 0 041 0 400 1 59 1 15 4 26 to
122. 12 130 2 7 iunc es WASHER I 2 7 i TR 7 eed al JOB E BS aJ 1 TM f w es TRANSMISSION WASHER U2 0 Pile dau Sa ai 51885 Figure 7 38 Installing converter housing bolts 10 Tighten the center support anchor bolt to 39 46 Ib ft 53 62 Nem fig 7 39 b Housing With 8 Bolt Top Cover 1 Refer to a 1 through 6 above for initial installation procedures except reference rebuild para 6 2 Install two 1 2 13 x 2 1 4 inch self locking bolts with flat washers into the recessed holes in the mounting pad at the 8 o clock position viewed from front of transmission figure 7 40 3 Into the next bolt hole counter clockwise install a 1 2 13 x 2 1 2 inch bolt with a lockwasher 4 Install a 1 2 13 x 3 3 4 inch bolt with lockwasher at the five o clock position older models use a 2 1 8 inch bolt Install T o t i ire Ar e pm a um V i i um SCREW 410 32 x 2 2 WASHER 10 o NET m M i i 51534 Fig 7 39 Installing pilot tube screw Copyright 1983 General Motors Corp 7 21 HT 740D HT 750D AUTOMATIC TRANSMISSIONS IDLER SPINDLE BOLT 12 13X 314 a QA a e p PTO IDLER GEAR EC Xm emt Fig 7 40 Installing top PTO gear retaining bolt three 1 2 13 x 2 1 8 inch bolts with lockwashers into the remaining holes b Tighten the two bolts installed in 2 above
123. 145 0 to 177 0 6880118 Solid blue 8 5 0 091 0 690 1 45 1 10 21 7 to 25 3 white stripe 2 31 17 5 36 8 27 9 96 6 to 112 6 6883300 Solid green 10 0 084 0 690 1 95 1 10 29 0 to 35 4 white stripe 2 13 17 5 49 5 27 9 128 9 to 157 5 6884701 Solid orange 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 2 33 17 5 42 9 27 9 145 0 to 177 0 6885166 Solid orange 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 white stripe 2 33 17 5 42 9 27 9 145 0 to 177 0 23012937 Solid white 9 0 098 0 949 2 27 1 94 9 4 to 11 4 2 49 24 1 57 7 49 3 41 8 to 50 7 40 Second clutch trimmer 6833940 Solid orange 85 0 121 0 950 2 38 1 94 29 to 35 valve primary yellow stripe 3 07 24 1 60 5 49 3 39 to 47 6833945 Solid blue 7 4 0 092 0 930 2 27 1 94 9 40 to 11 40 2 33 23 6 57 7 49 3 41 8 to 50 7 6839271 Solid white 10 0 103 0 940 2 56 1 94 20 to 22 yellow stripe 2 61 23 9 65 0 49 3 89 0 to 97 9 Fold out Ref 20 40 20 B 50 20 B 55 Spring Second clutch trimmer valve primary Trim boost accumulator Fourth clutch trimmer valve secondary Fourth clutch trimmer valve primary 2 3 relay valve Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Part No 6880045 6880118 23012937 6838989 6880118 6880274 6885166 6833940 6833945 6839271 6880045 23012937 6832462 6834528 Color Code oolid orange Solid blue white stripe Solid white oo
124. 2 NR Not referenced in paragraph 4 Examine parts especially 2 If the bearings are particularly dirty or passages after cleaning to make certain they are entirely clean Reclean them if necessary C Cleaning Bearings 1 Bearings that have been in service should be thoroughly washed in volatile mineral spirits 1 8 x 1 1 4 COTTER PINS 4 3 175 mm x 31 75 mm CHAIN BEAD CHAIN FLEXIBLE CABLE OR PLASTIC LINKS 4 3 APPROX SHEET METAL DISK 76 2 mm 9 MIN 229 mm 12671A Fig 4 6 Low sun gear and hub pins filled with hardened grease soak them in the spirits before trying to clean the m 3 Before inspection oil the bearings with the same type of oil that will be used in the transmission WARNING Never dry bearings by spinning them with compressed air spinning bearing can disintegrate allowing balls or rollers to become lethal flying projectiles Also spinning a bearing without lubrication can damage the bearing d Keeping Bearings Clean Since the presence of dirt or grit in ball bearings is usually responsible for bearing failures it is important to keep bearings clean during removal and installation Observance of the following rules will do much to ensure maximum bearing life 1 Do not remove the wrapper from new bearings until ready to install them Copyright 1983 General Motors Corp GENERAL OVERHAUL INFORMATION 2 Do not remove
125. 2 8 6 to 9 1 38 3 to 40 5 9 35 to 9 85 41 6 to 43 8 7 85 to 8 35 34 9 to 37 1 7 18 to 7 68 31 9 to 34 2 6 1 to 6 7 27 1 to 29 8 8 35 to 9 35 37 1 to 41 6 6 75 to 7 25 30 0 to 32 3 Fold out Ref 20 B 91 Spring 1 2 shift valve Mean dimension shown Part No 6835310 6837454 6837540 6838356 6838357 6838358 6838366 6880991 6880992 6880993 6881060 6881061 6883665 6884934 6884936 Color Code oolid green oolid yellow Solid red oolid blue yellow stripe Solid red oolid orange white stripe Solid yellow red stripe oolid blue red stripe Solid white red stripe Solid green white stripe Solid yellow orange stripe oolid blue orange stripe Solid white green stripe Yellow stripe oolid orange white stripe No Coils 13 10 8 8 13 WEAR LIMITS AND SPRING DATA Table 8 2 SPRING DATA cont Wire dia 1n mm 0 059 1 50 0 056 1 42 0 041 1 04 0 062 1 57 0 062 1 57 0 062 1 57 0 062 1 57 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 Copyright 1983 General Motors Corp Spring OD 1n mm 0 640 16 3 0 672 17 0 0 400 10 2 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 Free Length 1n mm 2 51 63 8
126. 20 x 4 inch bolts to retain the trimmer valve 2 Place the flywheel assembly as assembled pare 6 3 on a work table ring gear side detent lever while the 2 1 2 inch bolt is tightened to 9 11 2 into the flywheel mounting holes 7 59 Be sure Ib ft 12 15 Nem Tighten all 38 of the bolts to 9 11 Ib the sealring on the end of the input shaft is in place ft 12 15 Nem 7 59 10 position and attach a lifting bracket J 24365 opposite the CAUTION guide screw Retain the bracket with 1 2 20 bolts On models that include a lockup 4 Attach ahoistto the lifting bracket Align the flywheel assembly with the transmission cutoff valve body assembly see note following 6 above the signal tube must be installed into the hole nearer the center of the valve body The hole near the end of the valve body must remain open b Installation 1 Push flywheel assembly straight onto the transmission aligning guide screw J 24315 2 with b Oil Filter Oil Pan Refer to paragraph 7 one bolt hole in the converter for installation procedure for the oil filter and the oil pan Copyright 1983 General Motors Corp 7 31 HOIST ICE 1289 7 1 243080 CONVERTER 243 5 2 re HOUSING E rae PAGG naa Efe 4 j EE TURBINE pee 248315 2 CONVERTER FLYWHEEL ASSEMBLY PUMP 53776 J 24365 FLYWHEEL ASSEMBLY A CONVERTER PUMP 53777 Fig 7 60 In
127. 21 d Lift off housing 19 B foldout 23 and attached parts Remove gasket 28 e remove the lower rear output disconnect assembly remove four bolts 41 foldout 23 two bolts 3 and lockwashers 42 and 36 f Lift off housing 35 and attached parts Remove gasket 30 g To remove the upper rear output disconnect assembly remove six bolts 25 and lockwashers 26 h Lift off housing 6 and attached parts Remove gasket 1 1 Remove snapring 3 and output drive gear 2 j Refer to paragraph 6 32 for rebuild of the disconnect assemblies 5 4 SEPARATING TRANSMISSION DROPBOX FROM a Removal of Transfer Gear Housing NOTE Governor assembly 26 BJ foldout 19 must be removed from adapter housing 10 before loosening t h e transfer gear housing Refer to a for removal 1 Position t h e transmission front end downward and attach a hoist to the dropbox housing Put some lift tension on the sling 2 Loosen the twenty four bolts 18 B foldout 19 and 25 approximately three turns Mark the indexing of the dropbox to the adapter for correct reassembly angle 00 150 300 450 or 600 CAUTION The output drive shaft assembly must remain seated at all times during removal of dropbox Reference figure 5 4 Copyright 1983 General Motors Corp DISASSEMBLY OF TRANSMISSION LIFTING BRACKET ie yy HOUSING OROP BOX Fig 5 4 Removing dropbox housing fro m adapter 3 Gentl
128. 22 10 to 23 50 98 3 to 104 5 21 1 to 23 3 93 9 to 103 6 17 9 to 18 9 79 6 to 84 1 17 9 to 18 9 79 6 to 84 1 4 30 to 5 70 19 1 to 25 4 4 30 to 5 70 19 1 to 25 4 4 30 to 5 70 19 1 to 25 4 Fold out 19 B 20 B Ref 5 4 19 29 Spring First clutch piston release Low clutch piston release Low clutch piston release Lubrication check valve Modulator valve Third clutch trimmer valve secondary Mean dimension shown Part No 6831656 6831656 6880418 6886138 6831656 6880418 6836693 6839127 6880652 6833934 6838077 6838519 6880980 23012948 6880118 6880274 WEAR LIMITS AND SPRING DATA Table 8 2 SPRING DATA cont Spring Free Color No Wire dia OD Length Length Under Load Code Coils 1n mm 1n mm 1n mm 1n mm 16 N Solid green 11 5 0 041 0 385 1 29 0 82 4 30 to 5 70 1 04 9 8 32 8 20 8 19 1 to 25 4 Solid green 11 5 0 041 0 385 1 29 0 82 4 30 to 5 70 1 04 9 8 32 8 20 8 19 1 to 25 4 oolid blue 9 5 0 073 0 500 1 31 0 90 26 05 to 27 85 1 85 12 7 33 3 22 9 115 9 to 123 9 oolid orange 9 5 0 063 0 439 1 25 0 88 17 90 to 18 90 1 60 11 2 31 8 22 4 79 6 to 84 1 oolid green 11 5 0 041 0 385 1 29 0 82 4 30 to 5 70 1 04 9 8 32 8 20 8 19 1 to 25 4 oolid blue 9 5 0 073 0 500 1 31 0 90 26 05 to 27 85 1 85 12 7 33 3 22 9 115 9 to 123 9 oolid green 19 0 092 0 535 2 48 1 97 32 25 to 37 05 2 33 13 6 63 0 50
129. 3 4 b Change Internal 3 4 c Oil Capacity 3 4 d Oil and Oil Filter Change Procedure 3 5 3 7 OIL CONTAMINATION a Examine at Oil Change 3 6 b Metal Particles 3 6 c Coolant Leakage 3 6 d Auxiliary Filter models without hydraulic retarder 3 7 3 8 BREATHER 3 7 3 9 LINKAGE a General Information 3 7 b Selector Lever Instal lation and Adjustment 3 7 c Retarder Linkage Adjustment ee 3 8 d Fuel Control Actuator Adjustment 3 8 Copyright 1983 General Motors Corp TABLE OF CONTENTS cont Paragraph Page e Disconnect Control Linkage dropbox models only 3 8 3 10 SHIFT SPEED ADJUSTMENTS a Calibrated On Test Stand Or In Vehicle oes oue eden aiu 3 8 b Location of Adjusting CO MID ONG Sis esaet 3 11 c Checks Before Adjusting Shift Points o on d Calibration by Road Test MEMOD e caorann Db babebb Debt terea stud 3 11 e Alternate Method Using Speedometer Readings 3 12 f Calibration by Test Stand MICTHOG 3 12 3 11 EXTERNAL LINES AND OIL COOLER a External Lines
130. 30 Depress the valve plug and insert retainer pin 79 into the hole at the front of the valve bore 21 After S N 10299 install hold regulator 74 spring 75 v a 1 v e stop 76 washer 77 and adjusting ring 78 flat side first into bore L fig 6 20 of valve body 30 BJ foldout 20 22 Align the pin hole in valve stop 76 with the pin holes in the valve body Compress the spring and install retainer pin 79 into the valve body to retain adjusting ring 78 Be sure the adjusting ring is in the same position as it was before removal 23 Install priority valve stop 71 spring 72 and priority valve 73 into bore M fig 6 20 of valve body 30 B foldout 20 24 Prior to S N 2510066690 install modulator valve 18 longer end first spring 19 retainer washer 20 valve stop 21 and adjusting ring 22 flat side first into bore N fig 6 20 of valve body 28 B foldout 20 After S N 2510066689 install modulator actuator valve 23 modulator valve 24 spring 25 and adjusting ring 26 into bore N of valve body 28 25 Align the pin hole in valve stop 21 if stop is used with the pin holes in the valve body Compress the spring and install retainer pin 27 into valve body 28 to retain adjusting ring 22 or 26 Be sure the adjusting ring is in the same position as it was before removal 26 Install governor accumulator valve 66 spring 67 and valve stop 68 into bore R of valve body 30 B foldout 20 Align stop 68 a
131. 38 mm DIA 6 0 250 in 6 35 mm DIA HOLE Lb ER rik E RELL 222222 NS Ae 500 1 2224 a Ie I de 20030 T DIA 0 002 in 0 05 EN L AS 0 002 in 0 05 mm 0 360 in 9 14 mm PL 0 in 6 60 mm SWAGE BUSHING INTO HOLES USING BUSHING INTERLOCK SPLIT MUST BE TOOL J 26997 MORE THAN 45 FROM THE SWAGING HOLE 2 PLACES WHEN MOUNTED ON DIA FEATURES BUSHING INSTALLATION LOAD SHALL BE WITHIN THE TOTAL RUNOUT MUST BE 500 LB 2224 N SPECIFIED BY B IN DIRECTION SHOWN Fig 6 58 Sun gear shaft bushings installation requirements 3 Using bushing installer tool J 24201 long end press new bushing 24 to 0 360 inch 9 14 mm below end surface into the small OD end of shaft 25 ira NOTE 4 NS SWAGING TOOL ERE 226897 Use a minimum of 500 pounds 2224 Newtons assembly force on bushing installer 4 Install bushing 26 in the s a m e manner as bushing 24 except use short end of tool J 24201 Press new bushing 26 to 0 260 inch 6 60 mm below end surface into the large OD end of shaft 25 5 Using swaging tool J 26997 swage both SS n ra SHAFT ASSY bushings into holes in sun gear shaft fig 6 59 uv 6 If tool J 28489 is not available place shaft leer in lathe having a four jaw chuck Adjust the chuck to obtain a zero run out of diameter jig 6 58 Using a SET TUUM LM 1 inch 25 4 mm boring bar with a tool having a 1 32 in 1 0 78 mm radius machi
132. 4 44 1 04 10 2 40 4 29 2 19 0 to 19 8 6836976 Solid white 14 0 044 0 400 1 85 1 15 6 91 to 7 19 yellow stripe 1 12 10 2 47 0 29 2 30 7 to 32 0 6836977 Solid orange 16 0 047 0 400 1 85 1 15 7 79 to 8 11 1 19 10 2 47 0 29 2 34 7 to 36 0 6837539 Solid blue 11 0 041 0 400 1 72 1 15 5 44 to 5 66 white stripe 1 04 10 2 43 7 29 2 24 2 to 26 2 6837540 Solid red 11 0 041 0 400 1 75 1 15 5 73 to 5 97 1 04 10 2 44 35 29 2 25 5 to 26 6 6837541 Solid yellow 14 0 044 0 400 1 82 1 15 6 61 to 6 89 blue stripe 1 12 10 2 46 4 29 2 29 4 to 30 7 6837952 Solid green 14 0 044 0 400 1 87 1 15 7 10 to 7 40 1 12 10 2 47 6 29 2 31 6 to 32 9 Mean dimension shown 8 11 Copyright 1983 General Motors Corp out Ref 20 B 71 20 79 20 8 82 20 B 85 20 B 91 Spring Hold regulator valve 1 2 shift valve 1 2 shift valve 1 2 shift valve 1 2 shift valve Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Part No 6837953 6838088 6838367 6838368 6880319 6880320 6834536 6885065 6834536 6833935 6833941 6833942 6834576 6834903 6834943 6835309 Color Code Solid blue oolid blue yellow stripe oolid blue orange stripe Solid yellow red stripe oolid orange white stripe Solid green white stripe No Color Code Solid blue No Color Code Solid blue Sold blue white stripe Solid white oolid orange yellow stripe Solid whit
133. 40D HT 750D AUTOMATIC TRANSMISSIONS NOTE To prevent leakage pan screws must retain a 5 16 ft 7 Nem minimum torque after gasket set 5 On transmissions equipped with an eight bolt top and or side cover on the converter housing install items 21 through 24 A and or items 41 through 44 Tighten the bolts to 42 50 Ib ft 57 68 N m b Retarder Valve Body if Install retarder valve body gasket 8 B foldout 21 2 Install retarder control valve body assembly 9 onto the retarder housing 3 Retain the valve body with four 3 8 16 x 2 5 8 inch bolts two 3 8 16 x 3 3 4 inch bolts and two 3 8 16 x 4 3 4 inch bolts all with lockwashers Tighten the eight bolts evenly to 26 32 Ib ft 35 43 N m 7 20 INSTALLATION OF TRANSFER GEAR HOUSING ADAPTER ASSEMBLY TRANSFER GEAR HOUSING DISCONNECT CLUTCHES OUTPUT INPUT FLANGES a Iransfer Gear Housing Adapter Assembly B foldout 19 1 Attach 3 strand lifting sling to rear of adapter housing assembly 9 2 Remove the two bolts and lockwashers installed temporarily iniparagraph 7 9d 3 Lift off assembled adapter assembly 10 4 Install output shaft assembly 32 or 38 onto end of transmission main shaft CAUTION Do not bump governor support pin 13 5 Install gasket 8 with holes and cutouts aligned with those in main housing 6 Lubricate sealing lip of seal 11 and the sealing surface of output shaft with oil soluble grease 7 Carefully lift housing a
134. 4195 to the center support and remove the support assembly fig 7 5 8 Remove the snapring ig 7 4 Remove the second clutch plates except whenp ate s were selected by stack method These plates are now preset for proper clearance and should be retained as a pack for final installation b Gear Unit Second Clutch Center Support 1 Attach lifting bracket J 24196 to the assembled gear unit fig 7 14 Lower the gear unit carefully aligning the pinions of the rear planetary to mesh with the rear planetary ring gear Remove the lifting bracket de unm M EXTERNAL TANGED amp CLUTCH PLATE GEAR UNIT 53030 Fig 7 15 Installing second clutch plate 2 Install the second clutch plate pack removed in a 8 above or plate pack selected by the stack method The thinner external tanged plates should be installed toward the rear of the transmission housing eror 7 0 Begin with an external tanged plate and alternately install seven external tanged and six internal splined plates 3 Install the white color coded snapring that retains the second clutch pack fig 7 16 4 Install the third clutch pisbn assembly into the center support The lips of the sealring must be toward the cavity in the center support CAUTION Improper installation of the butt joint sealrings may cause transmission failure Refer to paragraph 4 6E for proper installation procedure 5 Install the butt joint sealrings onto
135. 43 FOLDOUT 21 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 113646 11133 Copyright 1983 General Motors Corp A Foldout 21 Lockup cutoff low shift and low trimmer B Foldout 21 R ly expl valve body assemblies exploded view Foldout etarder valve body assembly exploded view 1 Roller bearing 2 Transfer drive gear 3 Roller bearing 4 Bolt 7 16 14 x 1A 5 Lockwasher 7 16 6 Spindle retainer washer 7 Idler gear spindle 8 Roller bearing assembly 9 Internal snapping 10 Transfer idler gear 11 Spacer 12 Roller bearing assembly 13 Self locking nut 2 16 B 14 Single row ball bearing 15 Spacer 16 Spacer 17 Transfer driven shaft assembly 1 Bolt 1 2 13 x 1 1 4 8 A 2 Lockwasher 1 2 8 3 Cover 4 Adapter housing gasket 5 Plug 3 4 NPTF 6 Transfer gear housing 7 Plug 1 4 NPTF 8 Adapter housing gasket 9 Cup plug 1 10 Lockwasher 1 2 8 11 Bolt 1 2 13 x 1 1 4 8 A 12 Bearing retainer assembly 13 Bearing retainer 14 Drain tube 15 Oil seal 16 Baffle 17 Bearing retainer 18 Lockwasher 1 2 8 19 Bolt 1 2 13 x 1 1 4 8 A 20 Speedo drive shaft 18 Output shaft 19 Bearing and race assembly 20 Transfer driven shaft assembly 21 Output shaft 22 Needle bearing assembly 23 Transfer driven shaft 24 Transfer driven gear 25 Spacer 26 Spacer 2 Single row ball bearing 28 Spacer 29
136. 4305 nA 5 20 pump snapring tool J 26598 UN T CONVERTER 54304 Fig 5 21 Removing installing converter pump snapring Copyright 1983 General Motors Corp 5 9 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 6 Release the safety guards and rotate the adjusting nut to the stop nut Lift off snapring and remove splined spacer 26 Place tool J 26598 on a bench face down close the jaws and remove the snapring NOTE If special tool 4J 26598 is not available remove the snapring with snapring pliers Do not scrape the ground sleeve splines during removal Remove the converter pump from the converter housing fio 5 22 After S N 2082 and prior to the use of split outer race bearing 6752471 remove the converter pump fig 5 23 using tool J 25007 as instructed in items 9 through 12 below Refer to items 13 through 15 for removing converter pump with split race bearing 8 Using figure 5 23 as a guide place puller sleeve 4J 25007 4 onto the converter ground sleeve 10 Insert the feet of leg and nut assemblies J 25007 2 between the balls of the bearing assembly spacing them 900 apart T GROUND le LEEVE ROS mcr rm E MP NT s Pi Fig 5 22 Removing torque converter pump Jr22001 3 DIM 75007024 HOUSING LI 1 53769 Fig 5 23 Removing torque converter pump using special tool Rotate the legs to make the feet bear
137. 47D 13 50 in 343 mm HT 750CRD 14 50 in 368 mm HT 754CRD 14 50 in 368 mm HT 750DRD 15 75 in 400 mm HT 750DRD DB 23 47 in 596 mm C Clean Transmission Clean the exterior of the transmission Steam cleaning should be followed immediately by disassembly because condensation allowed to remain in the transmission could cause rust d Heconnect at Installation At installation all items should be reconnected A transmission jack is convenient to raise the transmission into mounting position The transmission should be filled with oil 5 7 and road tested after installation 4 8 WEAR LIMITS Refer to for general and specific information covering parts fits clearances and wear limits 4 9 SPRING SPECIFICATIONS Refer to the spring data table 8 2 in Section 8 for spring identification and specifications 4 10 TORQUE SPECIFICATIONS Assembly procedures in Sections 6 and 7 specify the torque requirements for all bolts and nuts Torque values are also presented on the foldout illustrations at the rear of this manual Torque values specified are for dry assembly except when otherwise noted Bolts and washers should be washed and dried before assembly Copyright 1983 General Motors Corp 4 16 Section 5 DISASSEMBLY OF TRANSMISSION 5 1 SCOPE a This section covers disassembly of HT 740D HT 747D HT 750CRD HT 754CRD HT 750DRD and HT 750DRD DB transmissions The disassembly sequence is contin
138. 4L Coach Fuel Economy and Fire Truck Second Gear Start 2C 2L 3L 4L HT 740D 1C 1L 2C 2L 3C 3L 4C 4L General Standard HT 754CRD 1C 2C 2L 3L 4L 5L General Lockup in 1st Hold Second Gear Start 2C 2L 3L 4L 5L Lockup in 1st Hold HT 750DRD 2C 2L 3C 3L 4C 4L 5C 5L General 1st Hold 1C 1L HT 750DRD 2C 2L 3L 4L 5L Hi Torque Rise 1st Hold 1C 1L Any Diesel in High Power to Weight Vehicles Coaches Fire Trucks etc High torque rise diesel having a full load governed speed equal to or less than 2100 RPM and a peak torque below 1300 RPM trucks Conventional Diesels in On Off Highway Trucks Conventional and high torque rise diesels in truck Any Diesel in On Off Highway Trucks High torque rise diesel hav ing a full load governed speed equal to or less than 2100 RPM and a peak torque below 1300 RPM On Off Highway Trucks converter pump and turbine are locked together and provide a direct drive from the engine As rotational speed of the forward clutch and shaft assembly decreases the lockup shift valve will release the lockup clutch c The shift point check table in para 3 10 shows the speed rpm required to shift from one gear to another during closed or open throttle on transmissions in the 1950 to 2700 rpm range It also shows at what rom the lockup clutch is engaged and disengaged The table is coded alphabetically to indicate engine application If your unit is not applicable to the tabl
139. 5 49 3 129 0 to 155 7 6833945 Solid blue 7 4 0 092 0 930 2 27 1 94 9 40 to 11 40 2 34 23 6 58 4 49 3 41 8 to 50 7 out Ref 21 23 21 16 n 43 21 B 13 Spring Low shift trimmer valve secondary Hetarder control valve Disconnect detent Disconnect detent Disconnect detent Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Part No 6839102 6880274 6885166 6838531 5171417 5171417 5171417 Table 8 2 SPRING DATA cont Color Code Solid white Solid blue red stripe oolid orange white stripe No color code No color code No color code No color code Copyright 1983 General Motors Corp No Coils 8 5 9 6 9 6 8 1 8 21 8 22 Wire dia in mm 0 091 2 31 0 091 2 31 0 092 2 34 0 105 2 67 0 059 1 50 0 059 1 50 0 059 1 50 Spring OD in mm 0 720 18 3 0 690 17 5 0 690 17 5 1 600 40 6 0 438 11 1 0 438 11 1 0 438 11 1 Free Length in mm Length Under Load in mm Ib N 21 60 to 39 80 145 0 to 177 0 32 60 to 39 80 145 0 to 177 0 32 6 to 39 8 145 0 to 177 0 19 51 to 23 85 86 8 to 106 1 18 0 to 22 0 80 1 to 97 9 18 0 to 22 0 80 1 to 97 9 18 0 to 22 0 80 1 to 97 9 Section 9 OWNER ASSISTANCE AND SERVICE LITERATURE 9 1 OWNER ASSISTANCE The satisfaction and goodwill of the owners of Allison
140. 50D SERIES TRANSMISSIONS t if if J 24216 01 ocd Fig 6 50 Installing fourth clutch piston 6 Hold the backplate firmly against the snapring Insert gage J 24192 and check the clearance at the location shown in figure 6 51 When clearance is satisfactory the thinner step of the gage will enter between the backplate and clutch plates the thicker s t e p will not The prescribed clearance is 0 080 0 120 inch 2 03 3 05 mm Any clearance measurement within this range is satisfactory but the nearer to 0 080 inch the longer the clutch will maintain satisfactory clearance 7 Remove the snapring backplate clutch plates and piston f r o m the clutch housing Keep the clutch plates in a pack 8 Grease oil soluble grease and install a new teflon seal ring 11 i n t o the clutch housing Be sure the lip of the seal ring is facing the bottom of the piston cavity 9 Place fourth clutch piston 9 on the work table spring bosses side up Grease and install new teflon seal ring 10 lip downward into the groove on the outside circumference of the piston A seal ring for the inside groove in piston 9 is not required 10 Lubricate the two sealrings with transmission fluid Centrally locate the piston in the housing bore Place the piston and housing in an arbor press and apply pressure evenly until the piston is properly seated SNAPRING STEEN 7 A Kp BACKPLATE 2 n Y es 2 ANY Fig 6 51 Fou
141. 51128 Fig 6 104 Installing shifter fork install a new bearing Press on the inner race of the bearing and seat it against the shaft shoulder 105 5 If the needle bearing race was removed from the shaft install a new race and retain it with the snapring fig 6 105 2 Install the detent spring and two detent balls fig 6 105 7 Install the shifter shaft by threading it clockwise i n t o the shifter fork fig 6 106 Install the assembled shaft into the output driven coupling while holding the detent balls until t h e y engage the inner diameter of the coupling Tap the outer race of Copyright 1983 General Motors Corp 6 65 HT 740D HT 750D AUTOMATIC TRANSMISSIONS OUTPLIT SHAFT i i d K 3 DETEHNT BALI DETEHMT BMAP RIME 51129 Fig 6 105 Installing driven coupling detent spring CHUITPAT SHAFT S113 Fig 6 106 Installing output disconnect shaft the ball bearing assembly until it seats on the shoulder in the body 8 If oil seal 19 A was removed from the retainer install a new oil seal Press the seal spring loaded lip first into the retainer until it seats lightly on the shoulder in the retainer 9 Install the gasket retainer six lockwashers and six 1 2 13 x 1 1 2 inch bolts fig 6 101 Tighten the bolts to 67 to 80 pound feet 91 to 108 N m 10 Push the shifter inward to engaged position detent and adjust it by rotating the shaft
142. 6 44 0 to 47 2 Fold out Ref 102 107 111 Mean dimension shown Spring 3 4 shift valve 3 4 relay valve Trimmer regulator valve Part No 6884948 6884949 6884950 6884953 6884954 23012950 23012951 23012954 23013267 23013269 23013271 23013274 6832462 6834528 6770763 6834527 Color Code Yellow stripe Blue stripe Solid green white stripe Green stripe Solid yellow white stripe Solid white blue stripe oolid orange green stripe Solid yellow green stripe oolid yellow oolid orange Solid blue yellow stripe oolid orange blue stripe Solid red Solid blue yellow stripe oolid orange oolid blue red stripe No Coils 12 12 14 8 19 WEAR LIMITS AND SPRING DATA Table 8 2 SPRING DATA cont Wire dia in mm 0 054 1 37 0 054 1 37 0 062 1 57 0 062 1 57 0 062 1 57 0 054 1 37 0 054 1 37 0 059 1 50 0 054 1 37 0 054 1 37 0 054 1 37 0 054 1 37 0 073 1 85 0 073 1 85 0 041 1 04 0 047 1 19 Copyright 1983 General Motors Corp Spring OD in mm 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 690 17 5 0 680 17 3 0 480 12 2 0 500 12 7 Free Length in mm 2 90 73 7 2 94 74 7 2 37 60 2 2 45 62 2 2 48 62 9 2 90
143. 7 16 3 60 9 29 2 14 0 to 15 1 9 0 098 0 949 2 27 1 94 9 4 to 11 4 2 49 24 1 57 7 49 3 41 8 to 50 7 WEAR LIMITS AND SPRING DATA Table 8 2 SPRING DATA cont Spring Free Fold Color No Wire dia OD Length Length Under Load out Ref Spring Part No Code Coils 1n mm 1n mm 1n mm 1n mm 16 N 91 1 2 shift valve 23012951 Solidorange 12 0 054 0 640 2 98 1 15 10 6 to 11 4 green stripe 1 37 16 3 75 7 29 2 14 4 to 15 5 23012954 Solid yellow 13 0 059 0 640 2 51 1 15 10 75 to 11 25 green stripe 1 50 16 3 63 8 29 2 14 6 to 15 3 23013269 Solid orange 12 0 054 0 640 2 69 1 15 8 9 to 9 6 1 37 16 3 68 3 29 2 39 6 to 42 7 23013267 Solid yellow 12 0 054 0 640 2 57 1 15 8 2 to 8 8 1 37 16 3 65 3 29 2 11 1 to 11 9 23013273 Solid orange 12 0 054 0 640 2 65 1 15 8 65 to 9 35 yellow stripe 1 37 16 3 67 3 29 2 11 7 to 12 7 96 2 3 shift valve 6833935 Solid blue 9 0 054 0 640 2 i7 1 15 8 6 to 9 1 1 37 16 3 b5 1 29 2 38 3 to 40 5 6833939 No Color Code 8 5 02106 0 930 2 18 1 65 23 8 to 28 2 2 69 23 6 55 4 41 9 105 9 to 125 4 6833941 Solid blue 13 5 0 062 0 640 2 15 1 15 9 35 to 9 85 white stripe 1 57 16 3 54 6 29 2 41 6 to 43 8 6833942 Solid white 12 0 054 0 640 2 50 1 15 7 85 to 8 35 1 37 16 3 63 5 29 2 34 9 to 37 1 6834902 Solidorange 13 0 059 0 640 2 41 1 15 9 95 to 10 45 1 50 16 3 61 1 29 2 44 3 to 46 5 6835310 Solid green 13 0 05
144. 75 and valve 74 After S N 10299 remove parts in item 19 below 19 Remove retainer pin 79 adjusting ring 78 spring washer 77 valve stop 76 spring 75 and valve NOTE Step 20 explains the removal of the 1 2 shift valve configuration used in early production 2nd gear start units Step 21 explains the removal of the 1 2 shift valve configuration used in late production 2nd gear start units Step 22 explains the removal of the 1 2 shift valve used transmissions that do not require 2nd gear start 20 Remove retainer pin 82 shift signal plug 92 signal plug 91 shift valve 90 and shift valve spring 89 21 Remove retainer pin 82 adjusting ring 88 valve stop 87 spring 86 modulated valve 85 1 2 shift valve 84 and spring 83 22 Remove retainer pin 82 adjusting ring 97 stop 96 spring 95 modulator valve 94 and 1 2 shift valve 93 23 Remove retainer pin 103 adjusting ring 102 spring 100 valve stop 101 and valves 98 and 99 24 Remove retainer pin 109 adjusting ring 108 spring 106 valve stop 107 and valves 105 and 104 25 Remove retainer pin 113 valve stop 112 spring 111 and valve 110 NOTE In earlier models valve stop 112 consisted of two separate pieces 26 Remove retainer pin 117 spring 115 valve stop 116 and valve 114 NOTE Refer to above Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS b Assembly foldout 20 NOTE
145. 9 0 640 2 51 1 15 10 75 to 11 25 1 50 16 3 63 8 29 2 47 8 to 50 0 6837454 Solid yellow 9 0 056 0 640 1 98 1 15 8 22 to 8 72 1 42 16 3 50 4 29 2 36 6 to 38 8 6838356 Solid blue 14 0 062 0 640 2 43 1 15 11 45 to 11 9 yellow stripe 1 57 16 2 61 7 29 2 50 9 to 53 2 6838357 Solid red 14 0 062 0 640 2 52 1 15 12 25 to 12 75 1 57 16 2 64 0 29 2 54 5 to 56 7 6838358 Solid orange 14 0 062 0 640 2 01 1 15 12 74 to 13 26 white stripe 1 57 16 3 65 3 29 2 56 7 to 59 0 Mean dimension shown Copyright 1983 General Motors Corp 8 15 Fold out Ref 20 B 96 Spring 2 3 shift valve Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Part No 6838366 6880991 6880992 6880993 6881060 6882078 6883665 6884941 6884944 6884945 6884946 6884947 6884948 6884949 6884951 6884950 Table 8 2 SPRING DATA cont Color Code Solid yellow red stripe oolid blue red stripe Solid white red stripe Solid green white stripe Solid yellow orange stripe Solid yellow white stripe Solid white green stripe Hed stripe oolid blue red stripe Solid green white stripe Solid yellow white stripe Solid white green stripe Yellow stripe Blue stripe Orange stripe Solid green white stripe Spring Free No Wire dia OD Length Length Under Load Coils 1n mm 1n mm 1n mm 1n mm 16 N 14 0 062 0 640 2 67 1 15 13 45 to 14 05 1 57 16 3 67 8
146. A manually controlled valve admits oil to a vaned chamber surrounding the rotor When charged the retarder assists in slowing the vehicle e Power Takeoff Provisions 1 Transmissions are equipped with provisions for mounting a power takeoff on the front upper left side of the transmission housing lower left side of the converter housing and the top of the converter housing 2 The PTO on the transmission housing is converter driven The PTO s on the converter housing are engine driven f Planetary Gearing Clutches 1 Ihree planetary gear sets establish the four forward speeds and one reverse in the HT 740 or HT 747 transmissions The planetaries are controlled by five hydraulic applied clutches gearing is in constant mesh 2 Four planetary gear sets establish the five forward speeds and one reverse in the HT 750 or HT 54 transmissions The planetaries are controlled by six hydraulic applied clutches All gearing is in constant mesh g Control Valve Body Assembly The control valve body assembly is the brain of the transmission It is hydraulically operated Its oil passages valves and springs are designed to guide the flow of hydraulic fluid to a pre designated area Through variations of pressure and spring tension the components in the valve body are hydraulically moved at the precise time redirecting fluid to its pre selected point Copyright 1983 General Motors Corp 1 6 GENERAL INFORMATION h O
147. AKE LIMITED WARRANTY The Jacobs Engine Brake a product of The Jacobs Manufacturing Company Vehicle Equipment Division is sold with the following warranty The Jacobs Engine Brake Is warranted to be free of defects In construction and operation under normal use and service for the Warranty Coverage periods set forth below THERE ARE NO REPRESENTATIONS OR WARRANTIES WHICH EXTEND BEYOND THE TERMS HEREOF OR THE DESCRIPTION OF THE PRODUCT CONTAINED IN THE CONTRACT FOR SALE Warranty Coverage Engine brake housing assembly and related attaching parts except seals O rings and gaskets one year or 100 000 miles 161 000 kilometers whichever shall first occur Attaching parts not of Jacobs manufacture and all control system components seals gaskets O rings and switches three months or 24 000 miles 38 600 kilometers whichever shall first occur Replacement Parts installed during the original Warranty Coverage period are warranted for the remainder of that period but not less than 3 months or 24 000 miles 38 600 kilometers whichever shall first occur Replacement Parts installed after the expiration of the original Warranty Coverage period on new equipment are warranted for 3 months or 24 000 miles 38 600 kilometers whichever shall first occur Under this warranty our factory is obligated to replace without charge any part returned to us which our examination discloses to our satisfaction to have been defective within the Warranty Coverage period measur
148. ANETARY CARRIER cr d ERE Sorrel ee t LR ST CLUTCH PISTON REAR PLANETARY CARRIER CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PESTON CLUTCH APPLIED F TORQUE PATH 52962 Fig 2 12 Fourth gear torque path HT 750CRD HT 754CRD g Fourth Gear Operation fig 2 12 Engine torque is transmitted through the lockup clutch as described in b above The forward and the third clutches are applied third clutch application anchors the sun gear s h a f t via the fourth clutch housing against rotation which prevents the integral center sun gear from rotating The forward clutch application locks the turbine shaft and main shaft together so they rotate as a unit The rear sun gear is splined to both the main shaft and the center ring gear and rotates at input s p e e d With the center sun gear stationary and the center ring gear rotating the ring gear drives the center planetary carrier pinions This rotates the center planetary carrier at a speed reduction This carrier and the rear planetary carrier are splined to the planetary connecting drum The rear carrier hub on the output side is splined to the low ring gear When the connecting drum rotates the rear carrier and the low ring gear rotate at the same speed This rotation causes the low ring gear to drive the low planetary pinions while the low sun gear which is splined to the rotating main shaft also drives the low pinio
149. ANSMISSIONS 2 If bearing retainer 12 B foldout 22 was used on the lower rear position of the dropbox install retainer gasket 8 and retainer assembly 12 Fasten the retainer onto the dropbox with eight 1 2 13 x 1 1 4 inch bolts 11 and lockwashers 10 Tighten the bolts to 67 to 80 Ib ft 91 to 108 N m 7 21 REMOVING TRANSMISSION FROM OVER HAUL STAND a Attach a hoist to the hdding fixture that is secured to the transmission b Remove all fasteners that retain the holding fixture and the transmission to the overhaul stand Hemove t h e transmission and fixture from the overhaul stand c Remove the four bolts and nuts that retain the holding fixture to the transmission Remove the fixture d Install any nuts bolts or washers that may have been blocked by the transmission holding fixture 65 Tighten the nuts to 83 100 Ib ft 113 115 Nem tighten the bolts to 67 80 Ib ft 90 108 N m 7 22 CHECKING SHIFT POINTS Refer to paragraph 3 10 for procedures covering checking and adjusting shift point speeds 7 23 POWER TAKEOFF COMPONENTS a Existing Installation 1 Space limitations will determine whether the PTO should be installed before or after the transmission is installed 2 The prescribed backlash between the drive gear in transmission and the driven gear in PTO is 0 005 to 0 025 inch 0 127 to 0 635 mm for engine driven PTO in converter housing 3 The prescribed backlash for converter dr
150. ATA cont Color Code Solid orange white stripe Solid yellow Solid blue Solid white yellow stripe Solid orange Solid blue white stripe Solid white Solid red Solid yellow blue stripe Solid orange Sold orange white stripe Solid yellow Solid blue Solid orange blue stripe Solid green Copyright 1983 General Motors Corp Spring Free No Wire dia OD Length Length Under Load Coils 1n mm 1n mm 1n mm 1n mm 16 N 9 6 0 091 0 690 1 69 1 10 32 6 to 39 8 2 31 17 5 42 9 27 9 145 0 to 177 0 12 5 0 080 0 940 2 96 1 10 15 95 to 17 65 2 03 23 9 75 2 27 9 70 9 to 78 5 7 4 0 092 0 930 2 27 1 94 9 40 to 11 40 2 33 23 6 58 4 49 3 41 8 to 50 7 10 0 103 0 940 2 56 1 94 20 to 22 2 61 23 9 65 0 49 3 89 0 to 97 9 10 0 099 0 940 2 18 1 94 6 2 to 7 4 2 50 23 9 55 4 49 3 27 6 to 32 9 8 5 0 092 0 690 1 45 1 10 21 70 to 25 30 2 32 17 5 36 8 27 9 96 5 to 112 5 9 0 098 0 949 2 27 1 94 9 4 to 11 4 2 49 24 1 57 7 49 3 41 8 to 50 7 8 5 0 092 0 780 1 68 1 10 32 6 to 39 8 2 33 19 8 42 7 27 9 145 0 to 177 0 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 2 33 17 5 42 9 27 9 145 0 to 177 0 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 2 33 17 5 42 7 27 9 145 0 to 177 0 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 2 33 17 5 42 9 27 9 145 0 to 177 0 12 5 0 080 0 940 2 96 1 10 8 30 to 10 30 2 03 23 9 75 2 27 9 36 9 to 45 8 7 4
151. ATIONS AND DATA 1 8 Section 2 DESCRIPTION AND OPERATION 2 1 SCOPE sss 2 1 m MOUNTING Direct Mount straight through models 2 1 b Remote Mount straight through models 2 1 Paragraph Page c Direct Mount drop box models ccccceecceeeeceeeeeeeeneeeseeeeeeeeaees 2 1 d Remote Mount drop box models 2 1 2 3 INPUT DRIVE a Direct Drive 2 1 b Remote Drive 2 2 2 4 TORQUE CONVERTER a Description 2 2 b Operation 2 2 2 5 CLUTCH a Description 2 2 b Operation 2 2 2 6 7TORQUE CONVERTER HOUSING 2 3 2 7 HYDRAULIC RETARDER 2 4 2 8 OIL PUMP ASSEMBLY a b Operation 2 4 2 9 FRONT SUPPORT AND VALVE ASSEMBLY 2 4 DESIGNATION OF CLUTCHES PLANETARY GEAR SETS 2 4 a Necessary for Clarity of Description 2 4 b Clutch Designations 2 5 c Planetary Gear Set Designations
152. B a Low and First Clutch Clearances NOTE Two methods of checking clutch plate clearance have been established One method is by direct measurement as outlined in items 6 and 7 below The alternate method is by stack dimension computation outlined in paragraph 6 33 If the stack method is used disregard 1 through 7 below 1 Place the transmission housing in a vertical position rear upward fig 7 8 2 Beginning with an external tanged clutch plate alternately install seven external tanged and six internal splined first clutch plates fig 7 8 3 Install two guide bolts 180 apart into the transmission housing Align and install the adapter housing assembly as assembled in para 6 25 and gasket Copyright 1983 General Motors Corp 7 4 ASSEMBLY OF TRANSMISSION new plates to establish the desired clearance Recheck INTERNAL SPLINED PLATE ine earns TANGED NV co b CM atari i 54043 Fig 7 8 Installing first clutch plates 4 Beginning with an external tanged clutch plate alternately install seven external tanged and six internal splined low clutch plates refer olig 7 the clearance as described above OUTPUT SHAFT REAR COVER 53037 Fig 7 9 Installing rear cover assembly HT 18 750CRD HT 754CRD HT 750DRD 5 Install the rear cover assembly as assembled Lara 6 26 and gasket onto the rear of the transmission housing and secure it with six 1 2
153. BOUT YOUR 1 JUL 79 ARE OBSOLETE RECOMMENDATION MAKE A CARBON COPY OF THIS AND GIVE IT TO YOUR HEADQUARTERS O O SENT The Metric System and Equivalents Linear Measure 1 centimeter 10 millimeters 39 inches 1 decimeter 10 centimeters 3 94 inches 1 meter 10 decimeters 39 37 inches 1dekameter 10 meters 32 8 feet 1 hectometer 10 dekameters 328 08 feet 1 kilometer 10 hectometers 3 280 8 feet Weights 1 centigram 10 milligrams 15 grain 1 decigram 10 centigrams 1 54 grains 1 gram 10 decigram 035 ounce 1 dekagram 10 grams 35 ounce 1 hectogram 10 dekagrams 3 52 ounces 1 kilogram 10 hectograms 2 2 pounds 1 quintal 100 kilograms 220 46 pounds 1 metric ton 10 quintals 1 1 short tons To change inches feet yards miles square inches square feet square yards square miles acres cubic feet cubic yards fluid ounces pints quarts gallons ounces pounds short tons pounds feet pound inches F Liquid Measure 1 centiliter 10 milliliters 34 fl ounce 1 deciliter 10 centiliters 3 38 fl ounces 1 liter 10 deciliters 33 81 fl ounces 1 dekaliter 10 liters 2 64 gallons 1 hectoliter 10 dekaliters 26 42 gallons 1 kiloliter 10 hectoliters 264 18 gallons 1 sq 1 sq 1 sq 1 sq 1 sq 1 sq 1 1 1 Square Measure centimeter 100 sq millimeters 155 sq inch decimeter 100 sq cent
154. Bolt 1 2 13x 2 11 non retarder models A 4 Plug 1 8 B 5 Drive screw 6 Name plate 7 Transmission housing assembly 8 Transmission housing 9 Plug 4th clutch check 10 Plain washer 3 8 11 Bolt 3 8 16 x 3C 12 Oil baffle 13 Bolt 1 4 20 x 1 1 2 2 D 14 Plain washer 1 4 15 Bolt 1 4 20 x 1 1 2D 16 Bolt 1 4 20 x 1 1 2 0 D 17 Plain washer 18 Bolt 1 4 20 x 1 1 2 D 19 Bolt 1 4 20 x 3 1 2 0 D 20 Bolt 1 4 20 x 3 15 D 21 Bolt 1 4 20 x 2 1 2D 22 Detent roller and spring assembly 1 Breather 2 Plug 1 8 B 3 Drew Drive 4 Name plate 5 Transmission housing assembly 6 Transmission housing 7 Fourth clutch check plug 8 Plain washer 9 Bolt 3 8 16 x 3 Center support C 10 Oil baffle 11 Bolt 1 4 20 x 1 1 2 2 D 12 Plain washer 13 Bolt 1 4 20 x 1 1 2 D 14 Bolt 1 4 20 x 1 1 2 O D 15 Plain washer 16 Bolt 1 4 20 x 1 1 2 D 17 Bolt 1 4 20 x 3 1 2 0 D 18 Bolt 1 4 20 x 3 15 D 19 Bolt 1 4 20 x 2 1 2 D 20 Detent roller and sprang assembly 21 Sealring 22 Oil filter 23 Bolt 5 16 18 x 3 1 4 3 F A 23 Filter tube sealring 24 Oil filter 25 Bolt 5 6 18 x 2 3 4 E 26 Washer 27 Spacer 2 28 Oil pan gasket 29 Oil pan 7 inches deep 30 Drain plug washer 31 Drain plug C 32 Heater plug 1 inch 33 Plug 1 8 inch 34 Hex washer head screw 5 16 18 x 5 8 23 F 35 In
155. Check the position of all components configuration of all valves and plugs and identification of all springs before installation P 1 a c e the valve body on a work table flat side upward Refer td figure 6 B foldout 20 and spring chart in All valves when dry should move freely by their own weight in their bores 1 Install relay valve 61 B foldout 20 larger diameter first soring 62 and valve spring spacer 63 into bore A Depress spacer 63 and install retainer pin 57 into its hole in valve body 30 NOTE In earlier models valve stop 60 consisted of t w o separate pieces 2 Install relay valve 58 spring 59 and valve stop 60 into bore e the valve stop and install retainer pin 56 into its hole in valve body 30 3 Install fourth clutch trimmer valve 51 smaller end first plug 52 secondary spring 53 primary spring 54 and valve stop 55 into bore C of valve body 30 4 Install second clutch trimmer valve 41 smaller end first plug 42 secondary spring 43 primary spring 44 and valve stop 45 into bore D of valve body 30 5 Install third clutch trimmer valve 31 B foldout 20 smaller end first plug 32 secondary spring 33 primary spring 34 and valve stop 35 into bore E of valve body 30 6 Install first clutch trimmer valve 36 smaller end first plug 37 secondary spring 38 primary spring 39 and valve stop 40 into bore F of valve body 30 onto valve body 30 7 Install trimmer bo
156. Copyright 1983 General Motors Corp 1 13 HT 740D HT 750D AUTOMATIC TRANSMISSIONS SPECIFICATIONS AND DATA CHART cont HT 700 SERIES GOVERNOR PRESSURE Governor Governor Pressure psi At rpm 6834473 103 112 1650 6834864 83 91 1650 6836769 59 65 1650 May be read from engine tachometer during lockup in highest gear Copyright 1983 General Motors Corp 1 14 Section 2 DESCRIPTION AND OPERATION 2 1 SCOPE This section describes the transmission components and explains their functions It also explains the hydraulic system and the torque paths 2 2 TRANSMISSION MOUNTING a Direct Mount straight through models 1 Mounting converter housing 16 Bj foldout to the engine bell housing and coupling transmission flywheel 12 A foldout 9 to the engine provides a direct drive from engine to transmission 2 This type of mounting requires a minimum of ten bolts including two at the uppermost bolt holes in the converter housing to properly retain the converter housing to the engine housing b Remote Mount straight through models 1 A remote type mounting is provided for those transmission that are mounted to the vehicle and separated from the engine 2 This type of mounting requires the transmission be supported at both front and rear A bracket from the frame to the side pads on the converter supports the front A second bracket supporting the rear may be mounted to the top pads on the transmission rear
157. Corp REBUILD OF SUBASSEMBLIES 2 Remove valve plugs 34 35 and 38 and valves 33 36 and 37 from their respective bores NOTE Refer to above b Assembly A foldout 21 NOTE All valves when dry must move freely of their own weight in their respective bores 1 Unless parts replacement is required the lockup cutoff valves removed in disassembly should be installed in the same location from which removed 2 Install valves 33 36 and 3 into their respective bores in valve body 29 3 Install valve plugs 34 35 and 38 into their respective bores Retain the valves with pins 30 31 and 32 6 10 CONVERTER HOUSING WITH 2 BOLT TOP COVER FRONT SUPPORT OIL PUMP a Disassembly Wu Place the converter housing front downward fig 6 22 Remove and discard the two front mind hub needle bearing and race from the front support hub NOTE A damaged or worn front support hub can be salvaged with guidance from the instructions on the instruction sheet in the sleeve and pin kit The kit contains one unfinished front support sleeve one sleeve retainer pin and one machining and installation instruction sheet Refer to Parts Catalog SA 1268 for the kit part number BOLT 2 3 4 51966 Fig 6 22 Converter housing components 2 bolt cover no retarder 2 Place a wood 2 x 4 51 x 102 mm through the converter housing access opening about 14 inches 356 mm into the housing fig 6 23 Remove
158. D HT 750D AUTOMATIC TRANSMISSIONS Table 8 1 WEAR LIMITS cont Description THIRD CLUTCH CENTER SUPPORT SECOND CLUTCH cont Third clutch running clearance refer to 7 11 GEAR UNIT AND MAIN SHAFT ASSEMBLY Thrust washer thickness Thrust washer thickness Front carrier bushing clearance on sun gear shaft 23 Thrust washer thickness Sun gear shaft bushing clearance on main shaft 36 A foldout 15 oun gear shaft clearance in support bushing 16 B foldout 14 Sun gear shaft clearance in carrier bushing 7 A foldout 15 Thrust washer thickness GEAR UNIT AND MAIN SHAFT ASSEMBLY Thrust washer thickness Thrust washer thickness Front carrier bushing clearance on sun gear shaft 23 Thrust washer thickness Sun gear shaft bushing clearance on main shaft 36 B faldout 15 oun gear shaft clearance in support bushing 16 foldout 14 Sun gear shaft clearance in carrier bushing 7 A foldout 16 Thrust washer thickness TRANSMISSION MAIN HOUSING Main housing reaction clutch plate tang groove depth FIRST CLUTCH External tanged clutch plate Thickness Cone External tanged clutch plate Thickness Cone Copyright 1983 General Motors Corp 8 4 Wear Limit in 0 090 0 0993 0 013 0 1161 0 013 mm 2 31 2 31 0 183 2 31 0 163 0 165 0 183 2 31 2 31 0 183 2 31 0 163 0 165 0 183 2 31 2 29 2 522 0 33 2 948 0 33 Ill
159. D bodies 6 Remove the seven remaining bolts that retain the cover plate or lockup cutoff valve fig 5 17 Remove the cover olate or lockup cutoff valve Refer to lockup cutoff valve body rebuild 7 Remove eighteen bolts from the control valve fig 5 18 Remove the selector lever detent retainer bolt Do not Copyright 1983 General Motors Corp 5 7 x T A ys AT a dir sd k ut Fig 5 15 Valve body assembly HT 750D 754D ye SS Nu i di qum EN 9 i 7 TN hp ran E a d E NH c Lu rie 124 2603 LOW TRIMMER VALVE Vt BODY aw 52976 Fig 5 16 Removing trimmer valve body HT 750 754 remove the bolt 0 725 long that retains the selector valve Models built prior to S N 10300 use this bolt to retain the manual selector valve 8 Remove the f our bolts two washers and baffle that retain the oil transfer plate 5 18 HT 740D HT 750D AUTOMATIC TRANSMISSIONS BOLT 14 20X 1 Lie 2 BOLT 14 20 112 i lt p m te Rar S Se c ER IE xm CEN 1 Fig 5 17 Removing lockup cutoff valve HT 750 754 Ly SELECTOR VALVE BOLT UTES LG A i CONTROL VALVES HB ed Ge T SELECTOR LEVER BODY ASSEMBLY j MN HP ea dM Er u DETENT t 1020210
160. D OPERATION LOCKUP CLUTCH FOURTH CLUTC TORQUE CONVERTER iu z THIRD CLUTC FIRST CLUTCH a ae FORWARO 7 SECOND 7 CLUTCH A CLUTCH lt tor erg mi mpm rd m PL ee ee ee ee but PR Hee CENTER PLANETARY 5 CARRIER FRONT PLANETARY CARR IER were SECOND CLUTCH PISTON FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON a 52963 Fig 2 17 Second gear torque path 750080 e Second Gear Operation f ig 2 17 The forward and first clutches are applied Refer to paragraph 2 27d for detailed explanation differing only in output shaft speed reduction of 3 19 1 Copyright 1983 General Motors Corp 2 39 HT 740D HT 750D AUTOMATIC TRANSMISSIONS T m 0 ONU Ups o ON THIRD CLUTCH 7 FIRST CLUTCH FORWARD SECOND LOW CLUTCH CLUTCH JC DER au Te BN PARE EL 1 mm punt i lel ce rum Mmi rates bal F rd i Hairs AE jip F LOW PISTON D LOW PLANETARY CARRIER FIRST CLUTCH PISTON HEAR PLANETARY CARRIER CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON See CLUTCH APPLIED E TORQUE PATH Fig 2 18 Third gear torque path HT 750DRD Third Gear Operation fig 2 18 The forward and second clutches are applie
161. D SERIES TRANSMISSIONS NOTE Refer to above b Assembly B foldout 12 A foldout 13 1 Position the retarder housing front downward on blocks as shown figure 6 35 onto the retarder 2 Install the gasket housing as shown ones Align the holes in the gasket with those in the housing 3 Refer td paragraph 6 10b l through 7 for assembling the front support and valve assembly 4 Install the front support and valve assembly onto the retarder housing and gasket 35 5 Install the bolts as shown in figure 6 35 Tighten the bolts evenly to 36 43 Ib ft 49 58 Nem 6 Using oil soluble grease to retain them install the bearing race flat side first and the needle roller bearing onto the support hub fig 6 36 7 If removed install plugs 20 foldout 12 into the retarder housing Use nonhardening sealer on the plug threads and tighten them 4 5 Ib ft 5 4 6 8 Nem 6 17 FORWARD CLUTCH AND TURBINE SHAFT a Disassembly B foldout 13 1 Remove hook type sealring 1 from the front of the turbine shaft 2 Remove bearing race 2 from the hub of forward clutch housing assembly 5 3 Remove two hook type sealrings 4 from the turbine shaft 4 Position forward clutch assembly 3 on a work table turbine shaft down b Remove bearing race 24 and bearing 25 from forward clutch hub 19 6 Remove snapring 23 and fourth clutch driving hub 22 7 Remove five each of clutch plates 20 and 8 Remove f
162. Dra CIMA 200 hp 149 kW DU oer EelllOSaso2225 05 9125222022 492 092 0 00 9 2055 1 35 hp x engine speed Dive dedi ddldauss 222 95 90295 40 992099092 0 a M c Mesas M aNUDEE 6 pitch 250 pressure angle 40 teeth oide mounting 8 o clock position a viewed from rear NOB Dd TAG rcsoiu2 2503050220 12 0 22 092 0 82 004 0 2 9 9 a SAE 8 bolt Intermittent rating do Ras Mas Boedo 260 hp 194 kW CS OMUIMMOUS FOI TIO CIS Ead 200 hp 149 kW EIU Oe OF T quac 844 x engine speed Drive gear itte uestis Miam 6 pitch 250 pressure angle 64 teeth Manual disconnect clutches optional at three locations Upper rear B In line with input Lower rear D position In line with output Lower front C In line with output Hydraulic retarder absorption socie fe 365 hp 272 kw at 2100 rpm OUIDUET ANG m m T MT Supplied by installer Copyright 1983 General Motors Corp 1 12 GENERAL INFORMATION SPECIFICATIONS AND DATA CHART cont Transmission Ratios mechanical Hatio Before S N 14198 14509 After Range Clutches engaged S N 14679 amp after S N 14678 S N 28004 HT 740D Neutral First HT 747D Firs
163. E TRIMMER REGULATOR 7 EXHAUST OR SUMP REAR GOVERNOR C RETARDER IN LOCKUP FEE D E ReTARDER OUT Ki LUBRICATION FEED OPEN ON HTR CLOSED ON CONVENTIONAL MAIN VA 22 CLOSED ON HTR OPEN ON CONVFNTIONAL SECONDARY CONVERTER REGULATOR VALVE CONVERTER BYPASS VALVE MAIN PRESSURE REGULATOR VALVE PII II HYDRAULIC RETARDER CONTROL VALVE Ay EFTA LUBRICATION FEED LUBRICATION REGULATOR CONVERTER OUT VALVE ch OPEN OPEN THROTTLE THROTTLE OPEN ON HTR CLOSED ON CONVENTIONAL 4 5 SHIFT SIGNAL VALVE 2 3 SHIFT a al C SIGNAL VALVE 3 4 SHIFT SIGNAL VALVE 4 5 RELAY FOURTH CLUTCH PRESSURE 3 z A Y LOCKUP B D OPEN ON CONVENTIONAL FORWARD a CLOSED ON CLUTCH MAIN ADJ j GOVERNOR n i THIRD CLUTCH DU i MANUAL SELECTOR VALVE MODULATOR NEUTRAL ACTUATOR START SWITCH ORIFICE 2 OR REGULATOR J i E v Sate rp TRIMMER HOLD 3 3 4 SIGNAL Ld mum n B REGULATOR TEM dl REAR GOVERNOR ORIFICE x ORIFICE REAR 1 THIRD CLUTCH BALL LOW CLUTCH 1 re 1 GOVERNOR Euge 2 3 RELAY CHECK PRIORITY VALVE VALVE e Yo
164. ECTION A Fig 6 55 Center support assembly 53757 Fig 6 56 Installing retainer rings onto third clutch piston 6 20 GEAR UNIT AND MAIN SHAFT ASSEMBLY HT 740D 747D a Disassembly A foldout 15 1 Using figure 6 57 las a guide proceed as follows 2 Remove thrust washer 1 from the front of front planetary sun gear 2 S 4 Remove front planetary carrier assembly 4 Refer to paragraph 6 23 for rebuild of the carrier assembly Remove thrust washer 5 b Remove snapring 6 f r o m the front of the planetary connecting drum 17 Remove front planetary ring gear 9 Remove center carrier assembly 10 Refer rebuild of the carrier assembly 69 Remove center sun gear and shaft assembly 7 and thrust washer 8 If bushing 24 or 26 A in the sun gear shaft assembly is worn remove them 7 Lift main shaft assembly 12 fig 6 57 from the gear unit Center planetary ring gear 13 and rear planetary sun gear 16 are attached Remove sun g e ar 2 and thrust washer Copyright 1983 General Motors Corp 6 38 1 Thrust washer 2 Front planetary sun gear 3 Thrust washer 4 Front planetary carrier assembly 5 Thrust washer 6 Internal snapring 7 Sun gear and shaft assembly 8 Thrust washer 9 Front planetary ring gear 10 Center planetary carrier assembly 11 External snapring blg 12 Main shaft assembly 13 Center planetary ring gear 14 Roller bearing race 15
165. EMENT Ha 191 gt e 7 Lo t E 2 je Jh LOW PRESSURE LINE R a CONTROL VALVE EXHAUST EX VALVE V gee SLAVE PISTON nm TO CRANK CASE Bunt CRANK CASE EXHAUST VALVE BRIOGE NOTE A DRONE UNIT SAME AS SUPPLY UNIT SHOWN MINUS SOLENOID SUPPLY VALVE INJECTOR PUSH ROD EXHAUST VALVES MASTER PISTON SPRING OPERATING DESCRIPTION OF JACOBS ENGINE BRAKE THEORY OF OPERATION Simply stated energizing the Engine Brake effectively converts a power producing diesel engine Into a power absorbing air compressor This is accomplished when desired by motion transfer through a master slave piston arrangement which opens the cylinder exhaust valves near the top of the normal compression stroke releasing the compressed cylinder charge to exhaust The blowdown of compressed air to atmospheric pressure prevents the return of energy to the engine piston on the expansion stroke the effect being a net energy loss since the work done in compressing the cylinder charge Is not returned during the expansion process EXHAUST BLOWDOWN Referring to the schematic drawing exhaust blowdown occurs as follows 1 Energizing the solenoid valve permits engine lube oil to flow under pressure through the control valve to both the master piston and the slave piston 2 011 pressure causes the master piston and Its extension to move down coming to rest on the injector rocker clevis 3 he injecto
166. ER PTO COVER GASKET BOLT 7 16 14 X 1 1 8 8 LOCKWASHER 8 amp 175B Fig 5 27 Removing top PTO idler gear spindle for replacement of other gear assembly components 3 Remove the eight bolts and lockwashers that retain the side PTO cover Remove the cover and gasket fig 5 27 On earlier models remove the 1 2 20 x 1 1 4 bolt lockwasher and retainer washer from the front of the side PTO gear spindle Remove the g e ar assembly as shown in figure 5 28 On later models remove the 1 220 x 3 3 4 inch bolt lockwasher and plain washer that retains the side PTO gear spindle fig 5 27 Install a 1 2 20 x 6 inch bolt to replace the 3 3 4 inch bolt and tighten it finger tight Using a mallet drive the bolt rearward while supporting the PTO gear When the spindle is free of the housing remove the bolt spindle and PTO gear i 1 astare a Ert ju SIDE MOUNTTNG PAD asiti Fig 5 28 Removing side power takeoff gear 7 Remove the sealring from the PTO gear spindle If the gear is damaged replace the gear assembly Refer M eere 14 for replacement of other gear assembly components 5 9 REMOVING CONVERTER HOUSING a Housing with 2 Bolt Top Cover no retarder 1 From inside the converter housing remove the two screws and washers that the pitot tube or steel block 29 Hemove seven bolts and washers from B inside of the converter housing 29 2 3 Re
167. ET CONVERTER HDUS ENG 53224 Fig 7 62 Installing transmission front cover 2 Install two 7 16 inch headless guide bolts into the front cover 1800 apart fig 7 62 3 Install cover gasket fig 7 62 4 a the cover gasket onto the converter housing fig 7 62 5 Install twenty of twenty two 7 16 14 x 1 1 2 inch bolts and lockwashers through the converter housing into the input drive cover Remove the guide bolts and install the remaining two bolts and lockwashers Tighten bolts to 42 to 50 pound feet 57 to 68 N m 7 19 INSTALLING EXTERNAL COMPONENTS a External Components 1 a modulator pressure valve actuator rod Retain the rod with a plastic cup plug 2 Install the modulator valve retainer and secure it with one 5 16 18 x 9 16inch bolt fig 7 64 Do not tighten the bolt at this time modulator actuator will be installed when the transmission goes into the vehicle 3 On transmissions equipped with a 2 bolt top cover install items 1 through 3 B foldout 11 Tighten the bolts to 26 32 Ib ft 35 43 Nem 52967 Fig 7 63 Installing modulator actuator rod MODULATOR RETAINER 52965 Fig 7 64 Installing modulator actuator retainer 4 On transmissions equipped with a six bolt cover on the transmission housing install items 58 59 60 and 61 B foldout 16 Tighten the bolts to 15 20 Ib ft 20 27 N m Copyright 1983 General Motors Corp 7 33 HT 7
168. Fuel System Brake System Electrical System Miscellaneous A Publication TM 5 4210 227 24 amp P 5 continued TM 5 4210 227 24 amp P 7 TM 5 4210 227 24 amp P 8 TM 5 4210 227 10 COMPLETE MANUAL TABLE OF CONTENTS Continued Section 9 10 11 Section Title General Information Installation Instructions Troubleshooting and Service General Information Engine less major assemblies Fuel System and Governors Air Intake System Lubricator System Cooling System Exhaust System Electrical Equipment Instruments and Protective Systems Power Take off and Torque Converter Transmissions Sections 10 and 11 not included Special Equipment Operation Tune up Preventive Maintenance Troubleshooting and Storage Parts List and Foldouts Tools and Equipment Introduction Tabulated Data Operator s Instructions Operator Maintenance Illustrations Operator s Manual Series 92 Engines Operator s Manual Series V 71 Engines Built in Parts Book for Detroit Diesel Engines Operator s Manual Fire Apparatus Chassis FOREWORD Descriptions instructions and parts listing pertaining to the Model QWT 85 are discussed throughout this manual under general headings Foldout illustrations and schematics are located at the rear of this volume The foldout format is provided in order that illustrations and schematics may be referred to while the supporting text is being examined and
169. HT 754CRD a Description 2 10 b Operation 2 10 2 18 J PLANETARY GEARING HT 750DRD a Description 2 10 b Operation 2 11 2 19 SPEEDOMETER DRIVE Straight Through Models a Description seees zd b Operation 2 11 2 20 GOVERNOR a Description 2 11 b Operation 2 11 2 21 CONTROL VALVE ASSEMBLY a Description ccecce EE b Operation 2 12 TABLE OF CONTENTS cont Paragraph Page 2 22 LOW SHIFT AND TRIMMERS VALVES a Description eeeee ONES o u MER 2 12 2 23 LOCKUP CUTOFF VALVES a Description ccccecceeeceeeceeeeeeseeeneees 2 12 b Operation HT 740D ID C TID 2 12 C Operation HT 750DRD 2 13 2 24 SECOND GEAR START HT 740 HT 747 HT 750CRD HT 754CRD a Description 2 13 b Forward Gear Operation 2 13 First Gear Operation 2 13 d Reverse Gear Operation early 4 5 2 13 e Reverse Gear Operation late models
170. IL PAN FILTER VALVE BODIES HT 750D 754D a Oil Pan Filter 1 Refer to paragraph 5 6a l 2 3 Remove the screw that retains the oil filter c Remove the oil filter fig 5 13 sealring and the oil filter spacer late models only Note the number of spacers removed 2 Models with cast iron pan 29 foldout 17 use three bolts 23 to retain the oil filter to the valve body Remove the three filter retaining bolts and the oil filter Remove sealring 21 from the neck of the filter tube 3 b Valve Bodies 1 Remove the lockup clutch feed tube and the 3 4 5 signal tube fig 5 14 Copyright 1983 General Motors Corp 5 6 DISASSEMBLY OF TRANSMISSION 534 RIPE Fig 5 14 Removing signal tube HT 750D 754D Fig 5 12 Removing oil filter screw HT 750D 754D Mage Ss NOTE Models not equipped with allrange lockup will not contain the lockup clutch feed tube 2 Remove bolts and B fig 5 15 Install two 1 4 20 guide bolts J 24315 3 into positions A and B 3 Remove the five bolts remaining In the low trimmer valve body fig 5 16 Remove the low trimmer valve body 4 Remove the one remaining bolt In the low shift valve body Remove the low shift P MES Ld valve body GOVERNOR Fi 7 SCREEN LOCATION 5 Refer to paragraphs 6 7 and 6 8 for 52973 rebuild of the low trimmer and shift valve Fig 5 13 Removing oil filter HT 750D 754
171. IRST CLUTCH Foldout 6 Model HT 750CRD HT 754CRD transmission hydraulic system schematic view Copyright 1983 General Motors Corp MODULATOR PRESSURE REGULATOR MODULATOR OPEN THROTTLE ORIFICE LOW CLUTCH TRIMMER YALYE ACTUATOR 1 2 SHIFT SIGNAL YALYE OPEN ON 2ND GEAR START CLOSED OM 2ND GEAR START errr saree GOVERNOR YALYE FOLDOUT 6 HT 740 HT 750D AUTOMATIC TRANSMISSIONS B RETARDER IN C coNvERTER IN Bl converter out i UN CM AC Aii aiy N BB moouator o Mun Ker be MEI Oo FRONT GOVERNOR LUBRICATION First TRIMMER REGULATOR EJ EXHAUST OR SUMP REAR GOVERNOR RETARDER IN 17 Lockup re p retarver our WE LUBRICATION FEED SECONDARY CONVERTER REGULATOR VALVE CONVERTER BYPASS VALVE MAIN PRESSURE REGULATOR VALVE FIRST CLUTCH Ria E HY DRAULIC RETARDER CONTROL VALVE uil emie e hed DOT LUBRICATION FEED LUBRICATION REGULATOR cum E CE as SS CS SEE A i SE e ihm m OT 22 Lo ee se at tee PE ne eh ow tc n re ee ef FRONT aS ll GOVERNOR TT at aaa
172. LIES 19 Place a straight edge across the surface of the oil pump and oil pump gears as shown in figures 6 28 6 29 Insert a thickness gage between the drive and driven gears and the straight edge If the gear end clearance exceeds 0 006 inch 0 15 mm replace the gear 20 Install the cover and retain it with the 1 4 20 x 5 8 inch flat head screw fig 6 24 Tighten screw 9 to 11 Ib ft 12 to 15 N m STRAIGHT DRIVEN i THICKNESS GEAR GAGE 5463h Fig 6 28 Checking oil pump driven gear end clearance STRAIGHT EDGE Qu s DRIVE eet aw THICKNESS GEAR GAGE stab Fig 6 29 Checking oil pump drive gear end clearance 21 Install the sealring if used around the cover outer Install two 3 8 16 x 6 inch guide screws J 24315 1 into pump at the locations shown 22 Lubricate the sealring if used and oil pump cavity in the housing fig 6 30 Install the pump assembly guiding the screws through the holes indicated 23 While holding the pump assembly in place install six 3 8 16 x 4 inch bolts to retain it remove guide screws to install last two bolts Tighten the bolts to 36 43 Ib ft 49 58 N m 24 If removed install plugs 18 B foldout 10 Use nonhardening sealer on the plug threads and tighten them to 4 to 5 Ib ft 5 4 6 8 N m NOTE Front support sealrings must not be installed onto the support hub until the converter housing and front support are install
173. LT 12 13X2 1 2 1d s E NUT 12 13 di E Pu Fig 5 1 Installing transmission overhaul stand MODULATOR RETAINER Fig 5 2 Removing modulator actuator retainer 4 models having a converter driven PTO refer to B foldout 16 Remove six bolts 61 six washers 60 cover 59 and gasket 58 5 Remove the four bolts that retain the governor cover and gasket fig 5 2 Remove the cover and gasket Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS LOW j E 15 w EH n Ts 82957 Fig 5 3 Removing modulator actuator rod 6 Carefully remove the governor by rotating it clockwise while removing it 7 Remove the bolt that retains the modulator retainer fig 5 2 Remove the retainer On earlier models remove the modulator actuator rod 5 3 5 3 REMOVAL OF MANUAL OUTPUT DISCONNECT ASSEMBLIES DROPBOX MODELS a Lower front or rear disconnect assemblies may be removed either before or after removal of dropbox 6 Bj foldout 22 from adapter 9 B foldout 19 b However if the top rear disconnect is used disconnect housing 6 foldout 23 and attached parts must be removed before removal of the transfer case Also snapring 3 and output drive gear 2 must be removed Refer to h and i below C To remove the lower front output disconnect assembly remove four bolts 20 Bj foldout 23 two bolts 22 and lockwashers 23 and
174. MANUFACTURING COMPANY VEHICLE EQUIPMENT DIVISION EAST DUDLEY TOWN ROAD BLOOMFIELD CONNECTICUT 06002 JACOBS SOLE LIABILITY ANDYOUR EXCLUSIVE REMEDY IS LIMITEDTOTHEOBLIGATIONSSET FORTH HEREIN AND JACOBS SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES 11 Jaco Vehicle Equipment Division The Jacobs Manufacturing Company Bloomfield Connecticut 06002 U S A Form 3879 Revised 12 80 Printed In US A 6 81 Allison Transmissions HT 700 D Series Service Manual A IMPORTANT SAFETY NOTICE IT IS YOUR RESPONSIBILITY to be completely familiar with the warnings and cautions described in this service manual These warnings and cautions advise against the use of specific service methods that can result in personal injury damage to the equipment or cause the equipment to be unsafe It is however important to understand that these warnings and cautions are not exhaustive Detroit Diesel Allison could not possible know evaluate and advise the service trade of all conceivable ways in which service might be done or of the possible hazardous consequences of each way Consequently Detroit Diesel Allison has not undertaken any such broad evaluation Accordingly ANYONE WHO USES A SERVICE PROCEDURE OR TOOL WHICH IS NOT RECOMMENDED BY DETROIT DIESEL ALLISON MUST first be thoroughly satisfied that neither personal safety nor equipment safety will be jeopardized by the service methods selected Proper service an
175. MENT PARTS a Ordering Information Refer to the current issue of Parts Catalog SA 1268 for parts information b Parts Normally Replaced The following parts are normally replaced at each transmission overhaul Gaskets Lockstrips Washers or snaprings damaged by removal Oil seals piston sealrings WARNING Do not burn discarded Teflon seals toxic gases are produced by burning Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS 51013 Fig 4 1 Work table 4 4 CAREFUL HANDLING During all rebuild procedures parts and subassemblies must be handled carefully to prevent nicking scratching a n d denting Parts which fit together closely and have proper operating clearance can bind if damaged Parts which depend upon smooth surfaces for sealing may leak if scratched This is very important concerning parts of the control valve body assembly valves when dry must move freely by their own weight Such parts should be carefully handled and protected during removal cleaning inspection and installation as well as being kept clean while in containers awaiting installation 4 5 CLEANING INSPECTION a Dirt Causes Malfunction All parts must be clean to permit effective inspection At assembly it is very important that no dirt or foreign material be allowed to enter the transmission Even minute particles can cause the malfunction of close fit parts such as valves b Cleaning Parts 1
176. MISSION HT 750CRD HT 754CRD a Converter Operation Power is transmitted hydraulically through the torque converter Theengin e drives the converter pump The m p throws oil against the vanes of the turbine imparting torque to the converter turbine shaft From the turbine oil flows between the vanes of the stator and re enters the pump where the cycle begins again When the engine is idling impact of the oil upon the turbine blades is negligible When the engine is accelerated the impact Is increased and the torque directed through the turbine shaft can exceed the engine torque by an amount equal to the torque ratio of the converter Converter operation is illustrated in first second third a n d reverse operation where it is most likely to occur b Lockup Operation Power is transmitted mechanically through the lockup clutch Application of the lockup clutch occurs automatically in selected ranges as a function of governor pressure When the lockup c 1 u h is applied the converter elements rotate as a unit at engine speed This provides a direct drive from the engine to the turbine shaft Lockup operation is illustrated in fourth and fifth gear operation Neutral Operation fig 2 8 Engine torque is transmitted through the torque converter as described in a above The forward clutch is not engaged Thus the torque is not transmitted beyond the fourthclutch hub Although the low clutch is applied two clutches
177. PREVENTIVE MAINTENANCE SHIFT POINT CHECK Engine Governor Speed RPM 1950 2050 2100 2200 2300 2500 2600 2700 2200 1950 2050 2300 2500 2100 2200 Throttle Selector Transmission Output Speed RPM at Start of Shift Position Position Shift Drive 3 Full Drive 2 Drive 1 Check for manual shift function only A AB AC AG Conventional Diesel Engine HT 7400 High Torque Rise Engine 7400 C F G R Y Conventional Diesel Engine No lst Lockup HT 740D Conventiona Diesel Engine Special Lockup Points HT 740D D Conventional Diesel Engine No 1st Lockup For 190 Coach HT 7400 AN AH AL Conventional Diesel Engine No 1st Lockup 2nd Gear Start HT 740D Copyright 1983 General Motors Corp 3 9 HT 740D HT 750D AUTOMATIC TRANSMISSIONS SHIFT POINT CHECK Engine Governor Speed RPM 2100 2200 2300 2500 2600 2700 2800 2900 1950 2050 2600 2700 1950 2050 2100 2200 2600 2700 2300 2500 amid wo xoc s m uw o vje of s a f om o jJ ja Throttle Selector Transmission Output Speed RPM at Start of Shift Position Position Shift Low 320 380 B25 960 Full Drive 4 1010 1085 1245 1535 1580 1680 Drive 3 Drive 2 Full Orive 1 Low J O U AJ AO Conventional Diese Engine HT 7500RD Check that automatic converter to lockup shift occurs Check for manual shift functioon only K M AF High Torque Ri
178. R UNIT SECOND CLUTCH HT 740D HT 747D or HT 750DRD a Center 5 16 b Gear BIO NERO TEM 5 16 Second Clutch 5 18 5 13 REMOVING REAR COMPONENTS HT 740D HT 747D a Governor nennen D Rear COVOLF siessr rrr ene eec 5 18 First IBID 5 18 Copyright 1983 General Motors Corp Paragraph Page 5 14 REMOVING REAR COMPONENTS HT 750CRD HT 754CRD a D Re COVEI 5 19 c Low Planetary and Clutch d First Clutch and Ring c OM 5 15 REMOVING CENTER SUPPORT GEAR UNIT SECOND CLUTCH HT 750CRD HT 754CRD a Supporting Gear Unit b Removing Components 5 21 5 16 REMOVING REAR COMPONENTS HT 750DRD d GOVEIMON o 5 22 D Rear COVER 5 22 c Low Planetary and Clutch d First Clutch and Ring GEAT T 5 24 TABLE OF CONTENTS cont REBUILD OF SUBASSEMBLIES 6 1 SCOPE ssssses 6 1 6 2 GENERAL INFORMATION FOR SUBASSEMBLY REBUILD a Tools Parts Methods b Cleaning Inspection c Torque Specifications d Wear Limits Spring Data e Plugs and Fittings f Cl
179. RD model the low clutch has a single function When engaged with the forward clutch it produces first gear b Description The low clutches in both t h e HT 750CRD HT 754CRD a n d the HT 750DRD models each contain thirteen clutch plates and a piston Six are internal splined clutch plates and seven are external tanged clutch plates The external tanged plates are held stationary by the adapter housing while the internal splined plates are free to rotate The piston for each model is positioned in its respective bore and retained there by twenty eight piston return springs the return spring retainer four retainer rings and a snapring C Operation B foldout 18 HT 750CRD HT 754CRD 1 When the low clutch is released internal splined clutch plates 15 are free to rotate Since low planetary ring gear 14 is splined to internal plates 15 it will also rotate freely 2 When hydraulic pressure is directed to the back side of low piston 6 B foldout 18 the piston compresses clutch plates 15 and 16 together This locks rotating internal splined plate 15 to stationary external tanged plate 16 preventing ring gear 14 from rotating 3 With the application of the forward or fourth clutch in conjunction with the low clutch a reaction within the planetary gearing will produce either forward or reverse rotation respectively at the output shaft d Operation A foldout 19 HT 750DRD 1 When the low clutch is released intern
180. REAR UPPER A v ue Pr DISCONNECT l4 109 528 er ix HOUSING EE e a we INE EIE 1 P pees ct gu War i ge j X of ques LU As M AE Wa JE Wu es REAR LOWER JISCONNECT HOUSING FRONT LOWER DISCONNECT ontu HOUSING TORQUE PATH 4277 Fig 2 22 Transfer gear torque path HT 750DRD DB 2 35 TORQUE PATHS THROUGH TRANSMISSION HT 750DRD DB a LFigure 2 22 shows the HT 750DRD with a transfer housing dropbox attached Since the transmission is an HT 750DRD the converter lockup neutral and shifting operations are the same as explained in paragraph 2 34 b The addition of a transfer gear housing dropbox does not change speed reduction ratios The dropbox has a 1 00 1 ratio Copyright 1983 General Motors Corp 2 44 Section 3 PREVENTIVE MAINTENANCE 3 1 SCOPE This section covers routine and periodic procedures required to maintain the transmission in good operating condition Included are instructions for inspection care of the oil system and breather linkage adjustment care of the external lines oil filter and oil cooler stall testing storage and checking oil pressures Troubleshooting information is tabulated at the end of this section 3 2 INSPECTION AND CARE The transmission should be kept clean to make inspection easier Check for loose bolts loose or leaking oil lines oil leakage and condition of control
181. RING ASSY TRANSFER HOUSING SPACER DRIVEN GEAR T E tr rn T i d 12 Gas iun Rer Tiel tini 51110 Fig 6 93 Installing rear output shaft bearing and spacer BAFFLE ii TM OIL SEAL RA B RETAINER E OIL DRAIN a TUBE TRANSFER HOUSING 81111 Fig 6 94 Installing rear bearing retainer assembly NOTE The angle at which the retainer is installed depends upon the angle at which the transfer REAR OUTPUT SHAFT SPACER TRANSFER HOUSING J ut 67 zi aa eS LA fu PT al ot E Fig 6 95 Installing rear output flange spacer case is installed on the transmission housing In any installation the oil drain tube should be aligned as closely as possible to a downward vertical line transmission in installed position 4 Install eight 1 2 13 x 1 1 4 inch bolts and lockwashers Tighten the bolts to 67 to 80 Ib ft 91 to 108 Nem Install the spacer onto the output shaft 16 95 Loosely install the nut the end of the output shaft 5 If a rear output disconnect assembly is used install gasket 8 B adapter 27 A foldout 23 washer 28 and six 1 2 13 x 1 1 4 inch bolts 29 Tighten the bolts to 67 to 80 Ib ft 91 to 108 Nem Install drive coupling 31 and snapring 32 6 Turn the housing over front up and install the spacer and front bearing assembly on the r
182. RIT y A T iki 1 gt i x i i RETARDER PLATE ASSEMBLY PIPE PLUG vair Wo BOLT 378 15 X4 007 BOLT 38 16 X 1127 8375 Fig 6 31 Locating retarder plate assembly bolts 2 Press the pin into its bore in the converter housing until the pin head is 0 300 inch 7 62 mm above the housing surface 3 Position the housing front downward on a clean flat surface 4 If plug 6 was removed install a new plug Coat its circumference with a nonhardening sealer and install it flat side first into the housing Drive or press it flush with to 0 010 inch 0 25 mm below the housing rear surface 5 Install four plugs 8 with sealer Torque plugs 4 5 Ib ft 5 4 6 8 N m 6 Install gasket 14 and align its holes with those in the converter housing 7 Install the retarder plate assembly and retain it with eighteen 3 8 16 x 1 inch bolts and one 3 8 16 x 1 1 2 inch bolt Tighten the bolts to 36 43 Ib ft 49 58 N m a Assemble and install the oil pump as outlined in paragraph 6 10b 15 through 21 Note that the oil pump includes two driven gears Copyright 1983 General Motors Corp REBUILD OF SUBASSEMBLIES 9 While holding the pump in position install six 3 8 16 x 3 inch bolts replacing guide bolts with last two Tighten the bolts to 36 43 Ib ft 49 58 N m 10 Lubricate with oil soluble grease and install sealring 1 B foldout 12 into the groove around retarder plate 2 11 If studs
183. S 24203 HT 7400 HT 750CRD 04203 re 5 a 7400 HT 7 SOCRD 4 ET DA M gem HT 754CRD dee 4 k D oou HT 750DRD J 24769 Po pe HT 750 DRD SHAFT dur Fig 6 81 Installing output shaft bushing J 24202 4 1 3485300 sgg Fig 6 80 Installing output shaft orifice plug rear of transmission as shown in figure 6 73 On later transmissions the snapring is not bevelled Be certain that the proper snapring is used to match the groove In the housing Be sure the snapring is expanded fully into the dec eet cre installing the lip type oil seal refer to paragraph 4 64 for seal preparation Install the oil seal spring E lip first Use Installer J 24202 1 and driver handle J 24202 4 to locate the rear of the seal 0 60 to 0 70 inch 15 2 to 17 8 mm in front of the parking brake mounting surface plane ic ERA 6 82 14 Coat the outer circumference of dust shield 32 A foldout 20 16 or 35 Bj foldout 22 with nonhardening sealer Install the shield flat side first 52953 into the rear cover Fig 6 82 Installing output shaft oil seal The rear edge of the shield must be flush with to 0 040 inch 1 0 mm below the rear surface of the cover Copyright 1983 General Motors Corp 6 55 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 15 If available install the output flange after coating the oil seal inner circumference with high temperature grease Tighten flang
184. SE PLATE 17730A Fig 6 5 Rivet removing fixture 5 Place guide plate J 29535 2 on top of converter turbine hub 10 Centrally locate each rivet in the guide plate holes 6 Install one clamping bolt 1 2 13 X 3 1 2 inch to retain the guide plate converter turbine and base plate together Tighten the bolt 50 Ib ft 68 N m 7 Place the turbine assembly and fixture in a drill press 8 Place drill guide J 29535 5 into guide plate J 29535 2 fig 6 6 Using a 1 4 inch drill drill approximately 3 16 inch deep 9 Place the drill guide in the next hole Rotate the guide plate and drill the rivet Continue until all the rivet heads have been removed 10 Place the turbine and fixture In a hydraulic press Install rivet remover tool J 29535 4 into the guide plate fig 6 7 Press out each rivet CAUTION Do not use a hammer to remove the rivets 11 Remove the guide plate retaining bolt 12 Inspect turbine 11 A foldout 10 for cracks distortion and abrasions If deficiencies are noted the turbine must be scraped 13 Inspect the rivet holes for burrs or swelling Deburr as necessary NSE 29535 5 y DRILL GUIDE CONVERTER E TURBINE adds Fig 6 6 Removing rivet heads from converter turbine SES HYDRAULIC E PRESS E 1205352 jagaa ES BOLT 12 13x 312 ee P LOCKUP uS He E zw DRIVE 5 aque jm zm Y LIC Ea m ics GEAR f ro
185. SMISSIONS NOTE Refer to above b Machining Driven Gear Bushing NOTE Do not remove bushing 17 from gear 18 if proper machining procedure cannot be used at installation of new bushing 1 Remove damaged bushing 17 from scavenge pump driven gear 18 2 Press a new bushing into gear 18 to 0 030 inch 0 76 mm below the surface of the gear 3 Check the ID of the bushing for runout Runout must not exceed 0 001 inch 0 03 mm Surface finish of the bushing should be 30 microinch 0 762 micrometer c Assembly A foldout 12 1 If bearing 23 or 34 was removed apply Loctite Retaining Compound 601 or equivalent onto bearing circumference and install bearing into bore of gear 25 or 32 Allow parts to dry for 2 hours min 2 Retain the bearing by placing washers 24 or 31 at each end of rivets 26 or 33 Peen the rivets onto the washers so that the peened end extends no higher than 0 150 inch 3 8 mm above the gear face 3 On later models bearing 23 is retained in gear 25 by two snaprings 22 Install the snaprings 4 If spindles 10 were removed install the spindles plain ends first into the inside of body 9 Press the spindles to 1 0 inch 25 4 mm above the inside surface of the body 5 If needle bearing 7 was removed press a new bearing to 0 04 inch 1 mm below the outside surface of body 9 CAUTION Press only on numbered end of bearing when installing needle bearings 6 If bearing 14 was removed press
186. Self locking nut 2 16 B Torque b ft Nem A 42 50 5 68 B 600 800 813 1085 21 Washer 22 Gasket 23 Drive sleeve assembly 24 Oil seal 25 Washer 26 Sleeve 2 Lockwasher 5 16 2 28 Bolt 5 16 18 x 7 8 2 B 29 Lockwasher 1 2 8 30 Bolt 1 2 13 x 1 1 4 8 A 31 Bearing retainer assembly 32 Drain tube 33 Bearing retainer 34 Oil seal 35 Baffle Torque loft Nem A 67 80 91 108 B 10 13 14 18 HT 740D HT 750D AUTOMATIC TRANSMISSIONS A Foldout 22 Transfer gears and transfer gear driven shaft exploded view 17580 B Foldout 22 FOLDOUT 22 163888 Copyright 1983 General Motors Corp Transfer gear housing exploded view 1 Disconnect clutch housing gasket 9 Output drive gear 3 External snapring 4 Output driven gear 5 Shifter fork 6 Disconnect clutch housing 7 Oil seal 8 Rod wiper seal 9 Shifter fork shaft 10 External snapring 11 Output shaft 12 Detent spring 13 Detent ball 2 14 Bearing retainer gasket 15 Single row ball bearing 16 Bearing retainer 17 Lockwasher 1 2 6 18 Bolt 1 2 13 x 1 1 2 6 A 19 seal 20 Shim 0 025 21 Shim 0 005 4 Bolt 1 2 20 x 1 1 4 2 A Lock strip Retainer Shim 0 025 Shim 0 005 4 Oil seal Bolt 1 2 13 x 1 1 2 6 B Loekwasher 1 2 6 Bearing retainer Single row ball bearing Bearing retainer gasket Output shaft mJ O
187. Spacer Pins Pin Installer Tool Holder 20 6 9 6 9 25 2 17 67 4 47 4 30 21 2 17 6 46 4 15 19 2 17 6 7 4 47 4 31 21 2 17 6 7 4 47 4 66 21 2 17 7 4 47 4 36 21 2 17 7 4 47 4 32 21 2 17 While applying pressure rotate pinions a n d feel for reduction of end play The pinions must rotate freely and have 0 008 inch minimum end play after swaging the pins 15 Swage the remaining pinion pin ends as instructed in 14 above 0 120 3 048 SWAGE BOTH ENDS OF SIX PINS SECURELY AS SHOWN GEARS MUST TURN FREELY 94938 Fig 6 67 Front planetary carrier assembly swaging location Copyright 1983 General Motors Corp 6 48 REBUILD OF SUBASSEMBLIES c Replacing Bushing in Front Planetary Carrier Assemblies NOTE Depending upon the amount of labor machining bushing time parts replacement and extent of rework complete replacement of t h e assembly may be warranted 1 Fabricate six dummy pins to dimensions shown in figure 6 68 2 Place the front carrier on a work table rear downward 3 Press the bushing from the carrier Do not scratch or score the bushing bore Refer td para 4 BUSHING TO BE FLUSH TO 0 010 0 25 MM BELOW THIS SURFACE 0 002 0 05 MM TIR BUSHING INSTALLATION LOAD MUST BE 525 LA 2335 N IN DIRECTION SHOWN BUSHING SURFACE 4 Place the carrier in a press rear downward 5 Ap
188. T 740D HT 747D Shift 1 2 40 rpm Shift 2 3 40 rpm Shift 3 4 40 rpm c Checks Before Adjusting Shift Points 1 When calibration is to be made during a road test or on a test stand that simulates road operation certain preparations must be made 2 Raise the temperature of the transmission fluid in the transmission or test stand to 160 to 200 F 71 to 93 C 3 Check the engine no load governor setting and adjust if required to con form to the transmission s engine speed requirements 4 Check the engine for satisfactory performance before making shift point adjustments 5 Check the throttle linkage that controls the mechanical modulator valve actuator on the transmission for proper travel routing and operation 6 Check the shift selector linkage for proper range selection 7 Provide accurate instrumentation required for observing speeds temperatures pressures etc d Calibration by Road Test Method NOTE Before road test determine the vehicle tachometer error with a test tachometer Make corrections for error as required in subsequent tests 1 Subtract 100 rom from the engine no load governed speed and record the remainder as the desired speed for all automatic upshifts to occur except the 1 2 shift in HT 750CRD models The 1 2 shift in the HT 750CRD must occur at 100 rpm below lockup engagement speed 2 If doubt exists regarding when t1ocku p is occurring in HT 750CRD HT 754CRD
189. TECHNICAL MANUAL ORGANIZATIONAL DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST FOR 85 AERIAL LADDER FIRE FIGHTING TRUCK NSN 4210 00 965 1254 HEADQUARTERS DEPARTMENT OF THE ARMY 5 NOVEMBER 1986 TM 5 4210 227 24 amp P 3 Publication TM 5 4210 227 24 amp P 1 TM 5 4210 227 24 amp P 2 TM 5 4210 227 24 amp P 3 TM 5 4210 227 24 amp P 4 TM 5 4210 227 24 amp P 5 COMPLETE MANUAL TABLE OF CONTENTS Section Section Title Introduction Tabulated Data Chassis Assembly Pump Assembly Ladder Assembly Hydraulic System Electrical System Pneumatic System Ladder Calibration and Adjustments Illustrations General Information Engine less major assemblies Fuel System and Governors Air Intake Systems Lubrication System Cooling System Exhaust System Electrical Equipment Instruments and Protective Systems Sections 8 through 11 not included Special Equipment Operation Tune up Preventive Maintenance Troubleshooting and Storage General Information Description and Operation Preventive Maintenance General Overhaul Information Disassembly of Transmission Rebuild of Subassemblies Assembly of Transmission Wear Limits and Spring Data Allison Automatic Transmission HT 700 Series Parts Catalog Supplemental Parts Information Drive Line Front Axle Rear Axle Steering System
190. The forward and the third clutches are applied The third clutch application anchors the sun gear shaft against rotation which prevents the integral center sun gear from rotating The forward clutch application locks the turbine shaft and main shaft together so they rotate as a unit The rear sungear is splined to both the main shaft and the center ring gear and rotates at input speed With the center sun gear stationary and the center ring gear rotating the ring gear drives the center planetary carrier pinions This rotates the center planetary carrier at a speed reduction shown This carrier and the rear planetary carrier are splined to the planetary connecting drum and rotate with it as a unit Thus the output shaft being splined to the rear carrier rotates at the same speed as the center planetary carrier Copyright 1983 General Motors Corp 2 27 HT 740D HT 750D AUTOMATIC TRANSMISSIONS TORQUE FORWARD CLUICH f THIRD ERO inp CONVERTER CLUTCH FANE Menus lm TURBINE i y PLANETARY FOURTH SECOND i CLUTCH SUN GEAR SHAFT 2 FIRST CLUTCH i I f T IN v F a LP n J p 1 anl ELO n al i 7 d T wur aaa i OUrPUT SHAFT REAR SUN GEAR apan PLANETARY ee Minas CLUTCH APPLIED CONNECTING S cu TORQUE PATH Fig 2 6 Fourth gear torque
191. UTOMATIC TRANSMISSIONS SPECIAL TOOLS Tool No Fig Item Description Ref Paragraph J 24203 38 Output shaft bushing installer J 24204 1 Clutch spring compressor set J 24204 1 2 Low and first clutch spring compressor J 24204 2 4 3 Bar and stud assembly J 24204 3 4 Forward amp fourth clutch spring compressor J 24205 A 98 opeedometer driven gear bushing remover and installer set J 24205 1 99 Speedometer driven gear bushing installer J 24205 2 100 opeedometer driven gear bushing remover J 24207 41 Front planetary bushing sleeve installer J 24208 D 10 Center support compressor set J 24208 1 11 Compressor bolt J 24208 2 4 2 12 Compressor sleeve J 24208 3 13 Compressor bar bar is also used as gear pack support J 24208 25 15 Selective snapring gage assembly J 24209 21 Fourth clutch lifting fixture J 24210 4 2 17 Low and first clutch piston inner seal protector J 24216 01 18 Forward clutch piston inner seal protector J 24217 4 3 36 Main shaft orifice installer J 24218 2 16 otator cam spring and roller retainer ring J 24219 4 2 20 Lockup valve and main pressure regulator spring compressor J 24221 89 Fourth clutch alignment fixture J 24310 53 Transmission holding fixture J 24314 43 Valve ring adjusting tool 3 10b 2 J 24315 4 5 104 Guide pin set consists of two J 1126 J 3387 2 J 6889 1 J 24315 1 J 24315 2 J 24315 3 J 24315 1 108 Oil pump guide screw 3 8 16 x 6 2 J 24315 2 4 5 110 Flywheel guide screw 3 8 24 x 2 2 5 5a 3
192. X USE MARKED PISTON BEFORE SIN 16801 1 3615 1 3878 6880204 1 3882 1 4148 6880205 DIMX USE MARKED PISTON BEFORE SIN 16801 13615 13878 6836718 Pos 1 8882 14148 6836715 pu 6836714 A 6836714 A AFTER SIN 16800 1 3615 1 3878 6885131 1 3882 1 4148 6885132 1 4152 1 4415 6885133 Fig 6 108 Fourth clutch stack dimension LE E O O E 14152 1 4415 6880206 D pp O S F E S 13882 14148 6885130 14521 4415 6885120 A Fig 6 107 Forward clutch stack dimension 2 Apply the specified load and measure dimension X 3 From the table inj figure 6 108 select the fourth clutch piston Use the parts measured and the selected piston in the fourth clutch assembly d First Clutch HT 740 Low Clutch HT 750 6835439 1 1 Stack the first clutch plates and piston 6834766 2 as shown in figure 6 109 X 980 1020 L8 Be sure the specific internal clutch plates designed for the unit are being used in this stacking procedure Refer to Parts Catalog USE PLATE FOR SPECIFIC MODEL 6 2 Apply the specified load and measure 6834680 5 dimension X 3 From the table inj figure 6 109 select DIM X PLATE PLATE the recommended clutch plates to satisfy the required FROM 6834680 6834766 2 5667 2 5534 ADD 1 REMOVE 1 2 5534 25214 First Clutch HT 750 2 5214 2 5081 REMOVE 1 ADD 1 2 5081 2 4948 REMOVE 2 ADD2 figure 6 110 Be sure the
193. act of the oil upon the turbine blades is negligible When the engine is accelerated the impact is increased and the torque directed through the turbine shaft can exceed the engine torque by an amount equal to the torque ratio of the converter Converter operation is illustrated in first second also third HT 750 and reverse operation b Lockup Operation Power is transmitted mechanically through the lockup clutch Application of the lockup clutch occurs automatically as a function of governor pressure When the lockup clutch Is applied the converter elements rotate as a unit at engine speed This provides a direct drive from the engine to the turbine shaft Lockup operation is illustrated in third except HT 750 fourth and fifth gear operation Copyright 1983 General Motors Corp 2 23 HT 740D HT 750D AUTOVMATIC TRANSMISSIONS 10 ROS FORNARDE S FRONT CLUTCH THIRD CONVERTER E CLUTCH A eid 1 CENTER PLANETARY FOURTH SECOND a CLUTCH CLUTCH H ev 525 n Y i IS A o e Iv Bn eer Fie MES Aes 3u d TE E emm NE i wi Mii Ein E Rs m pica CU aT i m 5 p 2 a 7 OUTPUT im SHAE REAR SUN GEAR REAR PLANETARY d CLUTCH APPLIED SUN GEAR CONNECTING SHAFT DRUM gt TORQUE PATH Fig 2 2 Neutral torque path HT 740D HT 747D C Neutral Operation fig 2 2 Engine torque clutch hub Although the fi
194. agraph 4 6f Install oil seal lip first into the bore of adapter assembly 9 Press or drive the seal inward until its rear surface is 1 165 to 1 175 inch 29 591 to 29 845 mm below the bottom outer machined bore 11 If orifice plug 36 or 39 located in the front end of output shaft 35 or 41 was removed use tool J 24369 and install a new plug Press the plug to a depth that will clear the front edge of the bore 12 If needle bearing 37 B foldout 19 was removed use tool J 25562 and install a new needle bearing to 0 150 inch 3 81 mm below the end of the shaft 13 If bushing 34 or 42 B foldout 19 was removed from shaft 35 or 41 install a new bearing and press it to 0 340 inch 8 686 mm below the end of the shaft 6 30 FLEX DISK ASSEMBLY a Disassembly A foldout 9 1 If flex disk assembly 2 has not been removed from the engine crankshaft remove it 2 Remove twelve self locking bolts 9 and separate plate 8 flex disks 6 and 7 and hub assembly NOTE Refer to above b Assembly Aj foldout 9 1 Install flex disk 6 onto hub assembly 3 aligning the dowel pin hole in the disk with pin 5 Washers attached to disk 6 must face toward hub assembly 3 2 Install flex disks 7 in the same manner 3 Install plate 8 aligning the plate with dowel pin 5 4 Install twelve self locking 12 20 x 3 4 inch bolts 9 through plate 8 disks 6 and 7 and into hub assembly 3 Tighten the bolts to 96 to 115 Ib f
195. al splined clutch plates 14 are free to rotate Since these plates are splined to the outside diameter of low carrier assembly 29 the carrier will also rotate freely 2 When hydraulic pressure is directed to the back side of low piston 6 Aj foldout 19 the piston compresses clutch plates 14 and 15 together This locks rotating internal splined plate 14 to stationary external tanged plates 15 preventing low carrier assembly 29 from rotating 3 With the application of the forward clutch in conjunction with the low clutch a reaction within the planetary gearing will produce a forward rotation at the output shaft 2 16 PLANETARYGEARING HT 740D HT 747D a Description A foldout 15 1 Ihe gear unit and main shaft assembly contain three planetary gear sets These because their functions overlap are identified as front center and rear planetary carrier assemblies Their identification was so designated because of their location in relation to the transmission and to each other 2 Each of the three gear sets contains a sun gear and a ring gear which are interconnected by the main transmission shaft and a connecting drum This interconnection of the planetary input reaction and output elements and connections with the forward and fourth clutches produces four forward speeds and one reverse speed b Operation A foldout 15 1 The front planetary assembly 5 used in conjunction with the center planetary assembly 16
196. all openings and breathers with moisture proof tape 3 Coat all exposed unpainted surfaces with preservative grease such as petrolatum MIL C 11796 Class 2 4 If the breather can be easily removed spray one ounce 30 milliliters of VCI 10 or equivalent into the transmission through the breather hole Also spray one ounce 30 milliliters through the fill tube hole If the breather cannot be removed spray two ounces 60 milliliters into the transmission through the fill tube hole 5 If additional storage time is required repeat steps 3 and 4 at yearly intervals d Storage One Year With Oil 1 Drain the oil and replace the oil filter element s TEE 2 Fill the transmission to operating level with a mixture of one part VCI 10 or equivalent to 30 parts Dexron or Dexron ll transmission fluid Add 1 4 teaspoon of Biobor JF or equivalent for each 3 gallons 11 liters of oil in the system NOTE When calculating the amount of Biobor JF required use the total volume of the system not just the quantity required fill the transmission Include external lines filters and the cooler 3 Run the engine for approximately five minutes at 1500 rpm with the transmission in neutral 4 Drive the vehicle Make sure the transmission shifts through all ranges If it is equipped with a converter lockup clutch make sure the lockup clutch activates 5 Continue running the engine at 1500 rpm with the tra
197. alve Copyright 1983 General Motors Corp 2 16 DESCRIPTION AND OPERATION causing an increase in main pressure This increase in pressure is necessary for higher clutch pressures to handle the high torque produced in reverse gear 8 On the HT 750DRD foldouts 7 and 8 first gear develops a high torque ratio Since high torque requires greater main pressure approximately 250 psi to apply and retain the low clutch forward regulator pressure is omitted in this gear Moving the selector valve to engage third gear will initiate a hydraulic flow of oil from the 2 3 relay valve to the main regulator valve This oil will force the regulator valve downward bringing main pressure to its normal state approximately 150 psi for the remaining automatic shifting operations g Hear Governor Circuit 1 Governor feed is merely main pressure directed to the governor valve centrifugal type governor driven by the transmission output controls the position of the governor valve The position of the governor valve determines the pressure in the governor circuit When the transmission output is not rotating governor pressure is negligible When the transmission output rotates governor pressure varies with the speed of rotation 2 Governor pressure is directed to the shift signal valves in all models and to the governor accumulator valve on later models Also some models utilize rear governor pressure to control lockup 3 The go
198. alve with retarder 4 Converter housing assembly 5 Bolt 1 2 13 x 2 1 2 Non retarder models B 61 Lubrication valve pin with retarder 5 Converter housing 6 Lockwasher 1 2 1 Non retarder models Torque Ib ft N m 6 Plug 7 Plain washer 1 2 2 with retarder 36 43 49 58 7 Stud 1 2 13x 1 2 20 x6 40 3 B 8 Bolt 1 2 13 x 6 1 4 2 with retarder E 67 80 91 108 Stud 0 003 oversize AR 9 Converter housing assembly 42 50 57 68 Stud 0 006 oversize 10 Converter housing 15 5 20 88 Stud 0 009 oversize 11 Dowel pin 2 4 5 5 7 Stud 0 012 oversize 12 Dowel pin 2 4 8 Pipe plug 1 8 4 C 13 Pipe plug 1 1 2 J 88 100 119 136 9 Lockwasher 112 14 Pipe plug 1 H 70 90 95 122 10 Bolt 1 2 13 x 6 7 D 15 Cup plug 3 4 110 130 149 176 11 Lubrication valve spring 16 Pipe plug 1 2 K 16 20 22 27 12 Lubrication valve 17 PTO gear spin e 83 100 113 135 13 Lubrication valve pin 18 Plain washer 1 2 21 28 28 38 14 Converter housing gasket 19 Lockwasher 1 2 e Ib ft Nem 20 Bolt 1 2 20 x 1 L 26 32 35 43 21 PTO cover gasket 15 65 20 88 22 cover 4 5 5 7 23 Lockwasher 7 16 8 67 80 91 108 24 Bolt 7 16 14 x 1 1 8 8 C 25 Pipe plug 1 2 K 26 Seal 27 Plug 1 5 16 28 Lockwasher 7 16 2 29 Bolt 7 16 14 x 2 2 C 30 Seal 31 Plug 3 4 M 32 Stud 1 2 T3 x 1 2 20 x 6 40 3 D with retarder Stud 003 oversize Stud 006 oversize Stu
199. ance is to alternately Install seven second clutch external tanged 0 095 Inch the longer the interval between clutch plate and six internal splined clutch plates 7 3 replacements will be Replace worn plates with new plates to establish the desired clearance Recheck the 2 Retain the plates with selective snapring as descibed above 155 157 fig 7 4 The snapring must be color coded white b Selecting Center Support Snapring b Selecting Center Support Snaprin 3 Remove the third clutch piston from the center support assembly If not previously removed Install lifting bracket If the stack method of selecting the second clutch components is used disregard 1 below Copyright 1983 General Motors Corp 7 2 ASSEMBLY OF TRANSMISSION DC J 24195 CENTER SUPPORT ANCHOR BOLT 53044 Fig 7 5 Installing center support assembly J 24195 into the recess between the sealrings grooves on the center support hub fig 7 5 4 Install the center support into the transmission housing lfig 7 5 Be sure the tapped hole in the support is aligned with the anchor bolt hole in the bottom of the housing 5 Remove lifting bracket J 24195 from the center support Install the special 3 8 16 x 2 1 4 inch anchor bolt into the support through the anchor bolt hole in the bottom of the housing fic 75 Tighten the bolt finger tight 6 Place the compressor sleeve J 24208 2 on the hu
200. and main pressure regulator valve 3 8 Using the spring compressor remove snapring 12 washer 11 valve stop 10 spring 9 and lockup shift valve 8 9 The spring compressor is not required for the remaining valve components Push inward against valve support assembly 16 and remove Snapring 19 Remove support assembly 16 seat 15 converter bypass valve 14 and spring 13 10 Remove the nineteen bolts remaining In the front support assembly fig 6 22 Lift off the front support assembly and gasket CONVERTER HOUSING J jA 14 20 518 cca p DIL SEAL DRIVEN M GEAR m ee Ren L PEN DRIVEN GEAR ALR ING WM SHAFT nas nes GEAR BODY 51U67 Fig 6 24 Oil pump and torque converter housing J 24219 MAIN PRES SURE D REGULATOR 50906 Fig 6 25 Removing or installing main pressure regulator snapring 11 If replacement is necessary remove the needle bearing from the bore of the Copyright 1983 General Motors Corp REBUILD OF SUBASSEMBLIES support hub fig 6 25 Special tool J 28557 may be used to remove the needle bearing 12 If parts replacement is necessary remove test plugs 18 foldout 10 from housing 16 13 Do not remove the ground sleeve from the front support If there is evidence of movement or damage replace front support and ground sleeve assembly 2 A foldout 13 14 Determine the serviceability of the sealring gr
201. and provide a more uniform regulator pressure k Lockup Circuit Actuated by front governor HT 740D HT 747D HT 750 1 The front governor circuit originates at the front pitot Rotation of the vaned pitot collector ring directs oil against and into the pitot orifice This produces a pressure in the front governor circuit which varies with the rotational speed of the collector ring Pressure increases as speed increases This pressure is directed to the top of the lockup valve 2 When front governor pressure or front governor pressure assisted by modulator pressure is sufficient to compress the spring at the bottom of the valve the lockup valve moves downward In this position the valve directs pressure to the lockup clutch piston which causes the lockup clutch to engage Main pressure applies the lockup clutch in models not equipped with lockup cutoff valves When lockup cutoff valves are included clutch apply pressure from the drive clutch engaged is used toa p 1 y the lockup clutch Early HT 750DRD models do not have first gear lockup Lockup Circuit Actuated by rear governor HT 740D HT 747D 1 Rear governor pressure varies with vehicle or transmission output speed T h e pressure created by t h e rotational movement of the governor is fed to the top of the lockup valve During normal operation in first gear this pressure never increases sufficiently to overcome the lockup valve spring Therefore lockup in fi
202. ange should be selected for normal load grade and traffic conditions with an open highway ahead Drive 4 HT 754CRD HT 750DRD should be selected for moderate grades and over the road operation with restricted speeds Drive 3 HT 7400 HT 747D HT 750CRD HT 754CRD should be selected for moderate grades and over the road operation with restricted speeds Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS Drive 3 HT 750DRD operating in heavy traffic is appropriate for Drive 2 HT 740D HT 747D HT 750CRD HT 754CRD is appropriate for operating in heavy traffic Drive 2 HT 750DRD should be selected when need for speed control requires a hold condition such as descending steep grades where additional engine braking is required or for operation on rough terrain Drive 1 HT 740D HT 747D HT 750CRD HT 754CRD should be selected when need for speed control requires a hold condition such as descending steep grades where additional engine braking is required or for operation on rough terrain Drive 1 HT 750DRD should permit the driver to operate the vehicle in areas with maximum performance on extremely rough terrain f Hydraulic Retarder Apply the hydraulic retarder to help reduce speed on curves or downgrades The throttle should be closed when using the retarder Retarder effectiveness is increased by downshifting g Towing All lubricating and clutch a
203. ansmission parts or assemblies 3 Required tools and fixtures are available as outlined in the Service Manual 4 Reasonable and prudent maintenance practices are utilized NOTE Service organizations and individuals a r e encouraged to contact their local DDA Distributor f o r information and guidance on any of the tasks outlined herein 1 2 SUPPLEMENTARY INFORMATION Supplementary information will be issued as required to cover any improvements which may occur after publication of this manual Check with your dealer to ensure you have the latest information 1 3 ORDERING PARTS a Nameplate The nameplate fig 1 9 is located on the right rear side of the transmission housing The nameplate displays the transmission serial number part number assembly number and model number All three of these must be supplied when ordering replacement parts or requesting service information b Parts Catalog All replacement parts should be ordered from your dealer These parts are listed in the Parts Catalog SA 1268 Do not order by illustration item numbers used on exploded views in this manual Copyright 1983 General Motors Corp 1 1 HT 740D HT 750D AUTOMATIC TRANSMISSIONS CONVERTER HOUSING ACCESS REAR COVER BRAKE COVER f MOUNTING PAD OUTPUT SHAFT Lt ee zu a n E Ta seid H ce e 15 E AE n 8 NW pa zd PAL RS T Fi EA e umo E AES T oorr pum EC mb TR e
204. anual consisting of five separate sections 1 1 2 This volume consists of the Jacobs Engine Brake Manual and 8 sections and is arranged as follows General Information Description and Operation Preventive Maintenance General Overhaul Information Disassembly of Transmission Rebuild of Subassemblies Assembly of Transmission Wear Limits and Spring Data Installation Manual for Sacobs Model 71 92 amp 71A 92A This Engine Brake is designed for use on the following Detroit Diesel Engine Models 4 71 8V 71 6V 92 6 71 12V 71 8V 92 6V 71 16V 71 16V 92 It will also fit any 71 or 92 series Detroit Diesel Engine that has the same 4 valve or 2 valve cylinder head design and valve spacing as the Engines listed above Jacl Vehicle Equipment Division The Jacobs Manufacturing Company Bloomfield Connecticut 06002 U S A SCHEMATIC DIAGRAM OF ENGINE BRAKE OPERATION FUEL RACK FUEL OFF GOVERNOR CONTROLLED t BRAKE OM ci TO DRONE UNIT CONTROL VALVES BUFFER STOP SCREW EXHAUST VALVE EXHAUST ROCKER ARM STEM CAP ALL CHECK V 3 WAY SOLENOID SUPPLY VALVE TO OTHER SUPPLY UNITS VARIABLE QUANTITY ENGINE LUBE SLAVE PISTON LVE n OIL FROM AO SCREW PUMP uad 0M PUMP MASTER PISTON HIGH PRESSURE 777 N eed MASTER PISTON LINE Seo EXTENSION cx DRAIN FROM 2 VALVE HEAD nasum IT nd ur D Se OTHER UNITS ARRANG
205. applied in second and reverse gears Shifting the selector valve from neutral to drive 5 D5 position or any other forward drive range D4 D3 D2 charges the forward clutch circuit and applies the forward clutch The first clutch remains charged except in D1 In D1 the first clutch exhausts and the low clutch engages Hydraulic fluid is directed from the selector valve to the forward clutch It is also directed through the priority valve to the 2 3 relay valve The unit is now in second gear except when the selector is at D1 position D1 gives first gear only Automatic shifting from second gear to progressively higher gears third fourth fifth will occur as vehicle speed increases refer to 8 below 5 Shifting the selector valve from neutral to reverse R charges the fourth clutch while the first clutch remains applied In reverse fourth clutch reverse signal pressure is also directed to the bottom of the 2 3 relay valve The pressure at this point prevents the relay valve from moving downward during reverse operation 6 First gear can be obtained only by manually shifting the selector lever into drive 1 D1 position This gear is not automatic Hydraulic fluid is directed through the bore of the 1 2 shift signal valve to the top of the 1 2 relay valve Hydraulic pressure forces the 1 2 relay valve against its spring f o r c e to the bottom of its bore thereby directing main pressure to the low trimmer valve and low c
206. apring 18 from the rear of main shaft 11 Removem ai n shaft 11 from sun gear 14 If replacement is required remove orifice plug 35 A foldout 16 from shaft 36 9 Remove snapring 12 fig 6 65 from sun gear 14 Remove sun gear 14 from center planetary ring gear 13 10 Remove bearing race 17 needle roller bearing 16 and bearing race 15 11 Remove snapring 21 f r o m the rear of planetary connecting drum 19 Remove rear planetar carrier assembly 20 from the drum Refer leach 6 23 for rebuild of the carrier assembly NOTE Refer to above b Assembly Al foldout 16 1 If orifice plug 35 A foldout 16 was removed from shaft 36 install a new one The orificed end of the plug enters the bore first Use installer J 24369 to properly position the plug fig 6 64 Copyright 1983 General Motors Corp 6 43 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 1 Thrust washer 2 Front planetary sun gear 3 Thrust washer 4 Front planetary carrier assembly 5 Thrust washer 6 Internal snapring 7 Front planetary ring gear 8 Center sun gear and shaft assembly 9 Thrust washer 10 Center planetary carrier assembly 11 Main shaft assembly 52942 12 External snapring 13 Center planetary ring gear 14 Rear planetary sun gear 15 Thrust race 16 Needle roller bearing 17 Thrust race 18 External snapring 19 Planetary connecting drum 20 Rear planetary carrier assembly 21
207. ar cover bowel PIN SNAPRING GOVERNOR SUPPORT PIN 52908 Fig 6 77 Installing speedometer driven gear bushing Y a Jo 4 EN ur E COVERNOR p WE a SUPPORT PIN SNAPRING 52948 Fig 6 76 Removing speedometer driven gear bushing Copyright 1983 General Motors Corp 6 53 HT 740D HT 750D AUTOMATIC TRANSMISSIONS REAR COVER Po 5 896 149 76 mm Q 5 886 1149 50 mm Q ec 77704 a A um ere L ff A oe gt ZZ LLA A j uS aaa al w 4 f SUPPORT PIN 0 PLUC 942BA Fig 6 78 Governor support pin location 3 If removed install the governor support pin using tool J 28684 If the tool is not available install the pin to the dimension shown in figure 6 78 Accuracy of location and concentricity with the governor bore is of the utmost importance when installing the pin 4 If removed install a new speedometer driven gear bushing fig 6 77 Use installer J 24205 1 to seat the bushing in the rear cover 5 Lubricate sealrings 5 and 6 Aj foldout with transmission fluid and install them into the grooves of piston 4 The lip of each sealring must face the rear of the piston toward piston cavity in rear COVer 6 Using inner seal protector J 24210 carefully install the piston into the rear cover fig 6 79 Use extreme care to prevent the lip of either seal folding back over itself If installation is difficult remove the piston and check th
208. ar housing dropbox Manual disconnect clutch housing Disconnect eluteh shift fork Disconnect clutch shift shaft Disconnect clutch output shaft Transfer drive gear Transfer idler gear Transfer idler gear spindle Disconnect clutch housing adapter Transfer driven gear Low planetary carrier assembly Rear planetary carrier assembly Gear unit connecting drum Low shift valve assembly Low trimmer valve assembly Center planetary carrier assembly Front planetary carrier assembly Oil pan Cover plate PTO drive gear Pitot tube Retarder plate assembly scavenge pump assembly PTO and seavenge pump drive gear Input shaft Flywheel HT 740D HT 750D AUTOMATIC TRANSMISSIONS E H LXI Lir iq 5 Foldout 4 Model HT 750 DRD DB transmission cross section view Copyright 1983 General Motors Corp FOLDOUT 4 FOLDOUT 5 HT 740 HT 750D AUTOMATIC TRANSMISSIONS FRONT GOVERNOR _ REAR GOVERNOR OPTION OPEN THROTTLE OIL FILTER R BYPASSIVALVE LOCKUP MAIN PRESSURE REGULATOR VALVE SECONDARY CONVERTER REGULATOR VALVE es LOCKUP CLUTCH LOCKUP FEED 5 D g L D gt EIL mm EE 1 4 A ri Spe amv w LAB Yj gi ie LUBRICAT d REGULATOR alg EM LUBRICATION SECOND CLUTCH DICERE 2 E 2 17 al
209. are quantities required Pin Remover Planetary Camer Press Support Installer Assembly Fixture Blocks Remover Adapter HT 700 All Front 1 4 16 HT 700 All Center 1 3 29 HT 740 D 747D Rear 1 3 29 2 HT 750DRD Rear 5 29 2 HT 754CRD HT 750CRD Rear 1 5 29 2 HT 750DRD Low 1 4 29 HT 754CRD HT 750CRD Low 1 5 29 Tools In the chart above are components of planetary rebuilding Kit J 25587 01 CAUTION Do not put pressure on the carrier Distortion of the carrier will damage it 11 Install the remaining pinion pins as instructed in the preceding paragraph 12 Remove t h e carrier assembly from the press fixture Install swaging tool holder J 25587 17 into the opening of the press fixture bed Install a swaging tool into the holder Install another swaging tool into the press fixture ram Lubricate both ends of the pinion pins with oil soluble grease 13 Position the carrier assembly rear end upward except the center carrier on the press fixture Use the proper support block to level the carrier while the lower swaging tool is supporting the lower end of one pinion pin 14 Apply sufficient pressure to the press fixture ram to firmly swage the ends of the pinion pins against the metal of the carrier illustrates a typical swage pattern NOTE Swaging pressure is approximately three t o n s for each pinion pin Pin Remover Swaging Installer Loading Guide Pin Swaging Tool
210. aro end i 25 T Tp b n huc e Pd i CLUTCH RS ares PISION J i pL ie CLUTCH HOUSING S243b Fig 6 49 Removing or installing fourth clutch spring retainer snapring NOTE Refer to above b Assembly A foldout 14 NOTE If the fourth clutch housing is replaced selection of a proper piston M S or T is imperative before seal ring installation or clutch plate clearance check is done If the fourth clutch housing is not replaced and a new piston is required make sure the identification letter stamped on the new piston is identical to that on the old piston 1 Place fourth clutch housing assembly 12 A foldout 14 on the work table flat rear side downward 2 Before continuing the assembly the clutch clearance must be established One method is by direct measurement as outlined in 3 through 6 below An alternate method is by stack dimension computation outlined EA If the stack method is used disregard 3 through 6 below 3 Install fourth clutch piston 9 into the clutch housing fig 6 5Q Do not install a seal ring into the fourth clutch housing or on piston 9 at this time 4 Beginning with an external tanged plate alternately install five external tanged plates and five internal splined plates into the fourth clutch housing 6 48 5 Install the backplate and snapring 52 Copyright 1983 General Motors Corp HT 740D HT 7
211. arrier of the front planetary carrier assembly anchored against rotation by second clutch application the rotating terring gear rotates the center sun gear shaft via the carrier pinions This sun gear is integral with the sun gear shaft assembly to which the front sun gear is also splined The rotating front sun gear rotates the front carrier pinons w h o s e carrier is anchored against rotating by the applied second clutch In turn the rotating front carrier pinions rotate the front ring gear which along with the center carrier is splined to the rear planetary through the connecting d r u m Rotation of the connecting drum drives the output shaft through the splines of the rear planetary carrier at a speed reduction shown in Copyright 1983 General Motors Corp 2 26 DESCRIPTION AND OPERATION oe FORWARD m SNNT um E Nae n SUN GEAR SHAFT are NU SEE TENERE TEE THIRD Fs ee aah Sassen Pe aN va ee P 1 i vce PLANETARY ma Sh CENTER id ro PLANETARY am FOURTH r SECOND CLUTCH CONNECT ING Misa puts CLUTCH AR SUN GEAR REAR PLANETARY CLUTCH APPLIED DER E gt TORQUE PATH ci 51918 Fig 2 5 Third gear torque path 7400 7470 f Third Gear Operation fig 2 5 Engine torque is transmitted through the lockup clutch as described in b above
212. arts involved inside oil pan Adjust linkage Replace or rebuild control valve assembly Repair or replace valves back off spring Replace or adjust actuator cable refer to vehicle service manual Change oil install new filter para 3 8 Refer to H Overhaul transmission Replace filter para 3 8 Replace seal Replace flange Copyright 1983 General Motors Corp 3 23 N lO aN po IO U In 1 4 IZ HT 740D HT 750D AUTOMATIC TRANSMISSIONS Table 3 1 TROUBLESHOOTING CHART cont Cause Remedy HIGH STALL SPEED refer to Oil level low 1 Add oil to proper level para 3 3 Clutch pressure low 2 Refer to D Forward clutch slipping 3 Rebuild forward clutch First clutch slipping 4 Rebuild first clutch Fourth clutch slipping reverse 5 Rebuild fourth clutch Low clutch slipping 5 speed 6 Rebuild low clutch para 7 4 LOW STALL SPEED refer to para 3 13 Engine not performing efficiently 1 Refer to engine manufacturer s manual may be due to high altitude or vehicle service manual Broken converter parts 2 Replace converter assembly CLUTCH SLIPPAGE IN ALL FORWARD GEARS Oil level low 1 Add oil to proper level Clutch main pressure low 2 Refer to C Forward clutch slipping 3 Rebuild forward clutch and replace piston sealrings oealrings on front support hub 4 Replace sealrings worn or broken CLUTCH SLIPPAGE IN FIRST AND REVERSE ONLY HT 740D First clutch slippin
213. asily and give a crisp detent feel in each position The linkage should be adjusted so that the stops in the shift tower match the detents in the transmission c Retarder Linkage Adjustment Clean and lubricate all hydraulic retarder valve linkage The retarder is applied when the valve moves upward out of the valve body Therefore it is important for normal operation with retarder Off that the linkage be adjusted so the valve returns to the retracted position If the linkage causes the retarder to be partially applied loss of lubrication pressure overheating or excessive drag will result and fuel consumption will be excessive If the valve does not have full travel 1 5 in 38 1 mm maximum performance of the retarder cannot be obtained d Fuel Control Actuator Adjustment 1 It is imperative the mechanical linkage be properly adjusted for efficient performance 2 Place the fuel control lever on the engine at full throttle position 3 Place the mechanical actuator cable at full throttle position against the mechanical stop 4 Adjust the clevis at the fuel control lever so the pin fits freely through the hole in the clevis making sure the lever is secure 5 Total cable control travel should not be less than 1 187 inches 30 14 mm or more than 1 56 inches 39 62 mm e Disconnect Control Linkage dropbox models only CAUTION Improper shifter shaft adjustment reduces lube oil flow to the disconnect clutch
214. ast idle air ir cylinder as shown it must be removed and replaced with Jacobs optional fast idle buffer switch which contains its own air cylinder Install the Jacobs switch as outlined below Remove and disassemble fast Idle air cylinder sp Install cylinder spring piston inlet plug retainer ring and locknut from fast Idle air cylinder Into Jacobs fast Idle buffer switch and clamp assembly Insert them in the order shown Separate buffer screw portion from fast idle buffer switch and complete the standard buffer switch installation Replace and lock fast idle switch to buffer screw Adjust switch bracket and PET to ine up with Detroit Diesel Housing to blower bolt as shown Remove bolt and washer and secure switch by placing mounting bracket between washer and bolt Tighten bolt and clamp Install air tube elbow into inlet plug and attach air tube between elbow and fast idle limiting air cylinder on top of governor housing With the fast Idle buffer switch properly installed the Engine Brake will operate only during deceleration and will automatically shut off when fast Idle activation occurs CLUTCH oU eh aimee a SENA S ies T CUM po SLT i A 4 AX Poy T Mount CLUTCH SWR SO e adjustable rod on switch actuator is in contact with clutch pedal arm ADJUSTMENT With Clutch pedal in relaxed position loosen actuator rod clamp so that switch clicks with rod In contact with clutch arm Tighten clamp
215. b fig 6 22 Install the needle bearing onto the race NOTE Grease both the race and bearing before installing with sufficient oil soluble grease to retain them 15 If the oil seal was removed from the oil pump body install a new seal Coat the oil seal bore in pump body 3 B with Perfect Sealer No 4 or equivalent Use seal installer J 24198 and driver handle J 24202 4 for driving or pressing the seal The lip of the seal must face inward toward rear of transmission If no installer is available press the seal lightly until it is flush with the front of the housing az828 Fig 6 27 Installing oil pump oil seal NOTE Installer J 24198 can be used with the transmission assembled except for the flywheel torque converter 16 If needle bearing 8 Bfoldout 10 was removed install a new bearing Place the bearing numbered end first onto installer tool J 28646A Attach handle J 8092 Install the bearing into driven gear 7 NOTE If an installer tool is not available the bearing may be installed w i t h a soft mallet Drive the bearing on the numbered end into driven gear 7 until the bearing is 0 001 0 005 inch 0 025 0 127 mm below the surface 17 If plug 4 was removed install new plugs Press the plug flush to 0 010 inch 0 25 mm below the surface 18 Install the driven gear and the drive gear into the oil pump body fig 6 24 Copyright 1983 General Motors Corp REBUILD OF SUBASSEMB
216. b of the center support fig 7 6 Place compressor J 24208 3 across the transmission housing Retain the compressor bar with two bolts 7 Compress the center support by applying a torque of 5 Ib ft 6 78 N m to the center screw J 24208 1 Determine the width of the snapring opening using gage J 24208 13 or 15 fig 7 6 Select one of the snaprings listed below gage lugs are color coded to match the snapring colors Select the thickest snapring that can be put into the groove 4 24208 1 le d 33127 a J25208 25 ausi du Fig 7 6 Checking selective snapring clearance Color code Thickness Blue 0 148 0 150 in 3 76 3 81 mm Yellow 0 152 0 154 in 3 86 3 91 mm White 0 155 0 157 in 3 94 3 99 mm Hed 0 158 0 160 in 4 01 4 06 mm 8 Install the selected snapring to retain the center support Be sure the gap of the snapring is at the top of the housing regardless of its position when removed 9 Remove compressor J 24208 3 and sleeve J 24208 2 Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS c Second Clutch Clearance NOTE If the stack method was used to select the first clutch components disregard 2 3 and 4 below 1 Before completing the assembly the clutch clearance must be established One method is by direct measurement as outlined in c 4 below An alternate method is by stack dimension computation outlined in If the stack method was used to
217. been reused e Before installing the retainer nut coat the threads of the nut with molybdenum disulfide grease Install the flange retaining washer and nut CAUTION The use of an impact wrench requires a means to hold the flange Failure to hold the flange can cause internal damage to the transmission f Tighten the nut 600 800 Ib ft 814 1085 N m 3 15 OUTPUT SEAL REPLACEMENT IN VEHICLE a Removal Foldout 2 1 Disconnect the vehicle drive shaft and remove the flange refer to Remove the speedometer driven gear from the rear cover AND BEARING 2 Remove the oil seal as described in paragraph 6 26a 2 3 Remove the snapring that retains the output bearing 4 Using puller tools J 24420 and J 24534 remove the rear bearing fig 3 5 Copyright 1983 General Motors Corp 3 15 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 818262 536 Fig 3 5 Removing rear bearing The legs of the bearing remover are designed to lock between the inner and outer races of the bearing Do not force the feet of the legs into position Forcing may damage the races b Remove the spacer and speedometer drive gear from the output shaft b Installation A foldout 20 1 Install speedometer drive gear 24 spacer 25 and output bearing 35 onto the output shaft Use installer J 24447 and driver handle J 24202 4 to seat the bearing 2 On assemblies prior to S N 5660 install beveled snapring 34 bevel toward rear
218. ble that the thick portion of the vanes is upward fig 6 12 Temporarily place two rivets 180 apart with the headless ends up Oe B ar la 9 VIEW AT B B STATOR 2 2 lt SS n CAM RIVET 2 ASSEMBLE WITH CAM STATOR CAM POCKETS IN POSITION SHOWN A DEEP END POCKET SN x VIEW SECTION A A IRECTION OF FREEWHEEL ROTATION RIVET 17593A Fig 6 12 Locating cam pockets into their grooves in the stator Using the rivets for alignment install the cam so that the deep end of each pocket is positioned as shown Tap the cam into place with a soft drift Remove the two rivets 11 Install cam washers 15 one on each side of the stator Install freewheel washer 18 and thrust washer 14 12 Align the rivet holes and insert ten new 1 4 X 2 5 8 inch rivets into the stator assembly from the side plate washer side and through the stator thrust washer 13 Place the stator assembly on base plate J 29121 2 fig 6 13 Be sure the rivet heads rest on the base plate between clearance holes Install top plate J 29121 4 and the 5 8 11 X 3 25 retaining bolt Strike the top plate with a rubber mallet to seat components Tighten retainer bolt to 60 Ib ft 81 N m 14 Place the stator assembly on fixture J 25587 1 219 Install stake tool J 29121 1 into the fixture head of J 25587 1 and tighten the thumb screw finger tight NOTE The amount of force to apply
219. bolts 19 washers 18 cover 17 and gasket 4 When a plain cover is used remove bolts 1 washers 2 cover 3 and gasket 4 4 On models which have a front mounted parking brake remove eight bearing A DRIVE GEAR fe d uw HOUSING e T F H Hoe AT Tu un od P i i T br he ri T 1 L 1 LI E ET ib 1 x 3 rEE E i i z LE i An a F 7 1 ey ak Pie igal Fig 6 85 Removing transfer drive gear dr wie 1 PN i D p OUTPUT DRIVE COUPLING SNAPRING ADAPTER Fig 6 86 Removing drive coupling snapring retainer bolts 30 B foldout 22 washers 29 retainer assembly 31 and gasket 4 If disassembly of the bearing retainer assembly is required refer to item 9 below 5 Remove spindle retaining bolt 4 Aj foldout 22 and washers 5 and 6 On spindles with a 500 20 UNF 1B thread use puller tool J 23544 for removal Spindles with a 1 00 12 UNF 1B thread must be Copyright 1983 General Motors Corp 6 57 HT 740D HT 750D SERIES TRANSMISSION drilled and tapped to 1 250 12 UNF 1B Use puller tool 11 Lift out the front bearing and spacer J 23544 A for removal Referenc figura 6 87 between the bearing and the gear fio 6 00 6 Remove idler gear 10 foldout 22 12 Remove the wood 2 x 2 in 50 8 x 50 8 bearings 8 and 12 snapring 9 and spacer 11 mm boa
220. bricant and the outside diameter with a nonhardening sealant Install the oil seal lip first into the transmission housing fig 6 84 Use installer J 26282 to properly locate the seal Copyright 1983 General Motors Corp 6 56 REBUILD OF SUBASSEMBLIES in the housing The seal must clear the chamfer in the housing bore 2 Hold detent lever 43 B foldout 16 so that the selector valve pin extends toward the inside of the housing fig 6 83 Slide the manual shaft through the opening in the housing oil seal and slot in the detent lever Install locknut 44 and retainer pin 48 Tighten the locknut to 15 20 Ib ft 20 27 Nem Refer to CAUTION 3 If breather 1 B foldout 16 was removed install the breather 4 If removed install nameplate 6 and drive screw 5 refer to a 6 and Note above 6 28 TRANSFER GEAR HOUSING AND GEARS NOTE If any output disconnect is used and it has not been removed refer to a Disassembly 1 If the drive gear and bearings where not removed icio remove them Hic 6 85 2 On front output disconnect models remove the snapring and drive coupling from the front of the rear output shaft Remove six bolts lockwashers adapter and gasket fig 6 86 3 On models which do not have a front output the bearing bore is closed When a B speedometer drive is included remove bolts 28 27 washer 27 sleeve 26 oil seal 24 washers 25 and 21 shaft 20 and gasket 22 Remove
221. ce the breather Pliers or a pipe wrench will crush or damage the stem and produce metal chips which could enter the transmission 3 9 LINKAGE a General Information Maintain proper adjustment of all linkage Periodic inspections should be made for defective parts Bent or worn parts should be replaced All moving parts must be kept clean and well lubricated CAUTION Manual selector shafts that are center drilled at their outer ends require an M10 x 1 5 6G n u t Metric thread Shafts that are undrilled require a 3 8 16 nut standard inch series Use of the wrong nut will damage both the shaft and nut Torque for either nut is 15 20 Ib ft 20 27 N m Excessive torque applied to the external selector lever retaining nut may damage the internal selector lever b Selector Lever Installation and Adjustment 1 To properly install the external lever rotate the manual selector shaft to a position t h a t is two detent notches from either end of its travel Install the external lever so that the flat sides of the shaft opening are parallel to the flats on the shaft Install the nut While holding the lever against rotation tighten the nut to 15 20 Ib ft 20 27 N m 2 Refer to vehicle manual for specific linkage adjustment procedures The following general procedures are applicable to most vehicles Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS 3 Ihe manual selector lever should move e
222. ch cotter pins installed in 7 9b 3 CAUTION Be sure all four cotter pins have been removed from the rear planetary ring gear Refer to note para 7 9b 3 5 Install bearing race 18 A foldout 19 into the recess in the front of the sun gear and hub assembly Retain it with oil soluble grease 6 Install bearing race 16 and needle bearing 17 onto the hub of the rear carrier assembly Retain them with oil soluble grease 7 Attach lifting bracket J 24196 to the main shaft of the gear unit assembly Attach a hoist to the eyebolt on the Copyright 1983 General Motors Corp 7 16 ASSEMBLY OF TRANSMISSION lifting bracket Lower the gear unit assembly as assembled in para 6 21 into the transmission housing engaging the teeth of the four carrier pinions and the internal splines in the carrier hub with the internal teeth of the rear ring gear and external splines of the output shaft respectively 8 Install 13 pre selected second clutch plates beginning with an external tanged plate and alternately installing seven external tanged and six internal splined plates fig 7 15 9 Install the white color coded snapring that retains the second clutch plates Be sure the snapring gap is located at the top of the transmission housing fig regardless of its position when removed b Center Support CAUTION The center support is fitted to the transmission housing with very little clearance It may bind during installation if
223. chining rear bushing in sun gear assembly shaft rotating during retrieval it could damage the bushing 8 Assemble the parts as shown ir figure 6 62 in the following manner Clamp the pilot tool in a vise fig 6 63 Insert the bushing pilot tool into the sun gear shaft end with newly machined bushing and fasten them together with the locking pin Using the same electric drill engage the shaft of the reamer in the pilot tool and machine the bushing Add cutting lubricant during machining operation Refer to the preceding caution when retrieving the reamer from the bushing 9 Check ID of bushings for runout Runout must not exceed 0 002 in 0 05 mm total indicator reading Surface finish should be 30 microinch 0 762 micrometer 10 Thoroughly clean shaft of chips and debris Copyright 1983 General Motors Corp 6 41 HT 740D HT 750D SERIES TRANSMISSIONS Ste 54287 Fig 6 62 Sun gear shaft assembly and tools for front bushing C Assembly foldout 15 1 If orifice plug 35 A foldout 15 was removed from main shaft 36 install a new plug Be sure the plug is pressed deep enough into the bore to clear the chamfer of the shaft Use installer J 24369 to position the orifice plug properly fig 6 64 2 Install rear planetary sun gear 16 fig 6 57 into the rear of center planetary ring gear 13 Retain it with snapring 11 3 Install the sun gear and ring gear assembled in 5
224. cover and the vehicle frame c Direct Mount drop box models 1 Mounting converter housing 16 Bj foldout to the engine bell housing and coupling transmission flywheel 12 A foldout 9 to the engine provides a direct drive from engine to transmission 2 Dropbox models utilizing this type of mounting require proper support It is recommended the transmission be cradle mounted between the mounting pads on the side of the engine housing and the mounting pads on the side of the drop box d Remote Mount drop box models 1 A remote type mounting is provided for those transmissions that are mounted to the vehicle and separated from the engine 2 This type of mounting requires the transmission be supported at both front and rear The front may be supported by attaching a trunnion mount bracket onto the front cover hub and to the vehicle frame The rear may be supported by attaching a bracket from the drop box side pads to the vehicle frame 3 The flywheel 12 A foldout 9 used on direct type mountings is removed and replaced by drive cover 7 Bj foldout 9 and front cover 4 4 A coupling or flange is installed onto the input shaft integral part to drive cover 7 providing a remote connection 2 3 INPUT DRIVE a Direct Drive steel laminated flex disk assembly 2 A foldout 9 connects the engine crankshaft and transmission flywheel assembly 10 This flywheel serves as the engine flywheel T h e inne
225. ctions of the input pump The first section directs oil red to the main pressure regulator valve item 2 above The second section directs oil black and green to the lubrication circuit and assists in providing oil to the converter in circuit 4 d Main Pressure Circuit foldouts 5 6 7 8 1 Main pressure red i s regulated by the main pressure regulator valve Oil from the pump flows into the valve bore through an internal passage in the valve to the upper end of the valve Pressure at the upper end of the valve forces the valve downward against the spring until oil yellow f 1 o w s into the converter in circuit When flow from the pump exceeds the circuit requirement the converter bypass valve opens and allows the excess to escape into the converter out circuit orange 2 Although main pressure is controlled primarily by the spring force below the regulator valve it is also affected by the presence of forward regulator pressure When this pressure is not present at the regulator valve main pressure is regulated at a higher value 3 Main pressure red is directed to several pointsin the hydraulic circuit These points will vary among models and depend upon the features such as lockup cutoff and hydraulic retarder e Converter Cooler Lubrication Circuit 5 6 7 8 foldouts 1 T h e converter circuit originates at the main pressure regulator valve Converter in oil yellow flows to the t
226. d 009 oversize Stud 012 oversize retarder 33 Converter housing gasket 34 Sealring 35 PTO drive gear spindle 36 Pipe plug 1 8 4 E 3 Bolt 7 16 14 x 1 1 2 19 C 38 Lockwasher 7 16 19 39 Seal 40 Plug 1 5 16 41 Bolt 7 16 14 x 1 1 8 8 C 42 Lockwasher 7 16 8 43 PTO cover A Foldout 11 Converter housing and ground sleeve exploded view B Foldout 11 Converter housing models with 44 PTO cover gasket retarder no PTO exploded view 45 Lockwasher 1 2 46 Bolt 1 2 20 x 3 3 4 G 47 Flat washer 2 48 Fillister head machine screw 2 F Copyright 1983 General Motors Corp 49 Lockwasher 1 2 3 Non retarded 50 Bolt 1 2 13 x 2 1 8 3 Non retarder B 51 Lockwasher 1 2 Non retarder 52 Bolt 1 2 13 x 3 3 4 Non retarder B 53 Plain washer 1 2 with retarder 54 Bolt 1 2 13 x 7 3 4 with retarder B 59 Lockwasher 1 2 3 with retarder SE UU Aam AR AR A B AR TA LOG nmoocu2 A cid c C with retarder with retarder with retarder A 1 Bolt 3 8 16 x 2 1 2 3 A 2 Lockwasher 318 3 3 Bolt 318 16 x 7 8 A 4 Scavenge oil pump assembly 5 Drive gear 6 Roller 7 Needle bearing 8 Body assembly 9 Body 10 Spindle 2 11 Drive gear 12 External snapring 13 Scavenge pump plate 14 Needle bearing 15 External snapring 2 16 Driven gear assembly 17 Bushing 18 Driven gea
227. d 3 to ensure that the end clearance is correct b the sealring and its groove with a liberal amount of oil soluble grease 6 Roll up the sealring to about half its free diameter and hold it that way for about10 seconds Being careful not to spread the sealring more than necessary slide it onto the hub Place one end of the sealring into the groove and gradually work the seal into the groove h Interference fit Parts Assembly of interference fit parts may be accomplished by heating and chilling the respective parts The female part can be heated in an oven or oil bath to 3000F 1490 C and the male part can be chilled in dry ice Either one or both parts may require a thermal process However if the chill process is used for a ferrous alloy part coat the components with transmission fluid to inhibit rust due to frost and moisture 1 Sleeve type Bearings The use of a locking compound is recommended to retain bushings and sleeve type bearings that have press fit tolerances One such compound is Loctite Sleeve Retainer 601 This compound or equivalent should be used j Bearings Ball or Roller 1 When installing a bearing on a shaft heat the bearing to 2000F 930C on an electric hot plate or in an oil bath Coat the mating surfaces with white lead and use the proper size installation sleeve and a press to seat the bearing NOTE Bearings must be heated long enough for sufficient expansion Heating ti
228. d Refer to paragraph 2 278 for detailed explanation of the torque path flow Refer to paragraph 1 6 for third gear ratio Copyright 1983 General Motors Corp 2 40 DESCRIPTION AND OPERATION LOCKUP CLUTCH TORQUE CONVERTER ROP Caen THIRD CLUTCH FIRST CLUTCH m FORWARD CLUTCH 7 SEE LOW CLUTCH CLUTCH ii EUM ABs LOW P ISYON a gt LOW PLANETARY CARRIER FIRST CLUTCH PISTON REAR PLANETARY CARRIER CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON RE CLUTCH APPLIED Fb TORQUE PATH 52963 Fig 2 19 Fourth gear torque path HT 750DRD Fourth Gear Operation fig 2 19 The forward and third clutches are applied Refer paragraph 2 27f for detailed explanation of torque path flow Refer to paragraph 1 6 for fourth gear ratio Copyright 1983 General Motors Corp 2 41 HT 740D HT 750D AUTOMATIC TRANSMISSIONS LOCKUP CLUTCH P FOU 1 TORQUE CONVERTER zi aia ed 3 THIRD CLUTCH FIRST CLUTCH LOMA AF E rm SECOND LOW CLUTCH ic FORWARD CEUTCH n if J d p Uer buen n i o LLLI abel She A Ii ME Low PLANETARY CARRIER T n ets D ro FIRS ECLUICH PISTON amp CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER
229. d planetary connecting drum 17 9 Install front planetary ring gear 9 splined outer end first into connecting drum 17 and secure it with snapring 6 Copyright 1983 General Motors Corp 6 42 REBUILD OF SUBASSEMBLIES A 2360 i AeA ED XN uu MAIN SHAFT 3 53746 Fig 6 64 Installing orifice plug into main shaft 10 Grease thrust washer 5 fig 6 57 and place it on the rear hub of front carrier assembly 4 Install the front carrier assembly 11 Install thrust washer 3 front planetary sun gear 2 and thrust washer 1 6 21 GEAR UNIT AND MAINSHAFT ASSEMBLY HT 750DRD HT 750DRD DB a Disassembly A foldout 16 1 Using figure 6 65 jas a guide proceed as follows Remove thrust washer 1 from the front of 2 sun gear 2 3 Remove sun g e ar 2 and thrust washer 4 Remove front planetary carrier assembly 4 Refer paragraph 6 23 for rebuild of the carrier assembly Remove thrust washer 5 fig 6 65 b Remove center sun gear and shaft assembly 8 If the bushings in shaft 8 are worn remove them 6 Remove snapring 6 from the front of planetary connecting drum 19 Remove front planetary ring gear 7 Remove center planetary carrier assembly 10 Refer rebuild of the center carrier assembly 7 Remove thrust washer 9 Lift main shaft 11 and its attached parts 12 through 18 from planetary connecting drum 19 8 Remove sn
230. d repair is important to the safe reliable operation of the equipment The service procedures recommended by Detroit Diesel Allison and described in this service manual are effective methods for performing service operations Some of these service operations require the use of tools specially designed for the purpose The special tools should be used when and as recommended WARNINGS CAUTIONS AND NOTES Three types of headings are used in this manual to attract your attention WARNING CAUTION NOTE is used when an operating procedure practice etc which if not correctly followed could result in personal injury or loss of life is used when an operating procedure practice etc which if not strictly observed could result in damage to or destruction of equipment is used when an operating procedure practice etc is essential to highlight LIST OF WARNINGS This manual contains the following warnings IT IS YOUR RESPONSIBILITY to be familiar with all of them Do not burn discarded Teflon seals toxic gases are produced by burning Never dry bearings by spinning them with compressed air A spinning bearing can disintegrate Also spinning a bearing without lubrication can damage the bearing When conducting a converter stall test the vehicle must be prevented from moving Both the parking and service brake must be applied and if necessary the vehicle should be blocked to prevent movement Warn personnel to keep clear
231. d the top of the transmission regardless of its position when re moved NOTE It may be necessary to compress the center support to install the selective snapring Continue assembly of Model HT 7400 HT 7470 at paragraph 7 11 Copyright 1983 General Motors Corp 7 13 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 57987 Fig 7 25 Installing center support snapring 7 9 INSTALLING REAR COMPONENTS HT 750DRD DRD DB a First Clutch and Ring Gear 1 Install one external tanged and one internal splined first clutch plate Into tile rear of the transmission fig 7 8 These plates should come from the front of the clutch pack removed in 7 4c 5 or first clutch plates selected by the stack method and the external tanged plate should be a thin plate if pack includes thin plates refer to para 7 2 2 Install the rear planetary ring gear stepped diameter upward 3 Install the remainder of the first clutch pack removed in 7 4 5 or selected by the stack method Begin with an external tanged plate and alternately install six external tanged and five internal splined plates fig 7 26 The last plate must be a thick external tanged plate refer to b Adapter Housin Carrier Low Clutch and Planetar 1 Place the adapter housing gasket on the adapter housing Retain the gasket on the housing with oil soluble grease Be sure all holes in the gasket are aligned with those in the housing 4 3
232. dapter assembly 9 into place over the shaft and guide the shaft through seal 11 8 Lower housing adapter carefully and engage dowel pins 14 and 15 9 Install twenty two 1 2 13 x 5 3 4 inch bolts two 1 2 13 x 7 3 4 inch bolts and twenty four 1 2 inch lockwashers Tighten the twenty four bolts to 67 to 80 Ib ft 91 to 108 N m Remove the hoist 10 Carefully install transfer drive gear 2 A foldout 22 with bearings 1 and 3 in place Install gear 2 long hub end first onto output shaft CAUTION Avoid any side movement of the shaft that can damage seal or governor support pin 11 If a threaded end shaft is used install the special 2 16 nut 43 B foldout 19 on end of shaft assembly 12 Tighten the nut to 15 to 20 Ib ft 20 to 27 N m and stake the lip of the nut into the rear of the gear at one of the six slots in gear hub CAUTION Front section of transmission must not be moved before installing the dropbox Rearward movement could allow the output drive shaft to damage the governor support pin and rear seal b Iransfer Gear Housing dropbox 1 Attach hoist and lifting bracket or 3 strand sling to the rear of the assembled transfer gear housing and hit the housing into position over the transmission front section Copyright 1983 General Motors Corp 7 34 ASSEMBLY OF TRANSMISSION 2 Check the angular poston oosition of the dropbox as Beers paragraph 5 4 Install rear gasket 44 fol
233. dels equipped with a second gear start feature will always start in second gear and progress to its highest gear when the selector lever is placed in any positione xcept drive 1 D1 8 The various drive ranges limit the highest gear attainable by introducing a pressure which prevents rear governor pressure from upshifting the signal valves unless a governor pressure well above that normally attained is reached This pressure isa regulated reduced pressure derived from main pressure at the hold regulator valve Main pressure is directed to the hold regulator valve through the hold feed line when the selector valve is at drive 4 D4 drive 3 or drive 2 D2 position The pressure produced in the hold regulator valve is directed to the 4 5 shift signal valve when the selector valve is at drive 4 D4 The hold pressure is directed to the 3 4 and 4 5 shift signal valves when the selector valve is at drive 3 position With the selector valve in drive 2 D2 position the pressure is directed to the 2 3 3 4 and 4 5 shift valves 9 Hold regulator pressure at each shift signal valve will push the upper valve upward and raise the pressure at which the lower valve will be pushed upward by rear governor pressure Thus when hold regulator pressure is present no upshift can occur at that shift signal valve except at an elevated speed p Clutch Circuit Drive Ranges HT 750DRD foldouts 7 8 1 There are six clutches
234. dels that do not have 2nd gear start 15 Install 1 2 shift valve spring 89 1 2 shift valve 90 signal plug 91 and 1 2 Copyright 1983 General Motors Corp 6 13 HT 740D HT 750D SERIES TRANSMISSIONS shift signal plug 92 smaller diameter first into bore K of valve body 30 20 16 Align the pin hole in signal plug 92 with the pin holes in the valve body Compress the spring and install pin 82 into the valve body 17 Install 1 2 shift valve spring 83 1 2 shift valve 84 1 2 modulator valve 85 spring 86 valve stop 87 and adjusting ring 88 into bore K of valve body 30 B foldout 20 18 Align the pin hole in valve stop 87 with the pin holes in the valve body Compress the spring and install retainer pin 82 into the valve body to retain adjusting ring 88 Be sure the adjusting ring is in the same position as it was before removal 19 Install shift valve 93 shorter end first modulator valve 94 spring 95 valve stop 96 and adjusting ring 97 flat side first into bore K of valve body 30 B foldout 20 20 Align the pin hole in valve stop 96 with the pin holes in the valve body Compress the spring and install retainer pin 82 into the valve body to retain adjusting ring 97 Be sure the adjusting ring is in the same position as it was before removal NOTE Before S N 10300 install hold regulator valve 74 spring 75 valve stop 76 and a holding regulator valve plug into bore L of valve body
235. dout 19 holes with those in adapter A 3 Carefully lower the dropbox into place and seat bearing Aj foldout 22 into the bearing bore in the dropbox 4 Install twenty one 1 2 13 x 1 3 4 inch bolts 18 B foldout 19 with lockwashers 19 through the thicker bosses 5 Install three 1 2 13 x 1 3 8 inch bolts 25 with lockwasher 24 into the remaining three holes having thinner bosses Tighten the 24 bolts to 67 to 80 Ib ft 91 to 108 N m 6 If cup 5 BL foldout 22 used with shaft assembly 32 B was removed coat the OD of the plug lightly with nonhardening sealer and with cup side out press the plug to the bottom of the bore c Output Manual Disconnect Clutches NOTE The assembly parts and procedure for installing the upper rear lower rear and lower front disconnect clutch housings to the transfer gear housing is similar The installation procedure listed below is for only one disconnect clutch housing but is applicable for all three disconnect housing installations All peculiar parts will be noted 1 Install manual disconnect output clutch gasket 30 A foldout 23 2 Position and install disconnect housing 35 and associated parts as assembled ri paragraph 3 Install two 1 2 13 x 2 1 2 inch bolts 37 and lockwasher 36 Install four 1 2 13 x 1 1 2 inch bolts 41 and lockwasher 42 Tighten all six bolts to 67 to 80 Ib ft 91 to 108 N m NOTE Note the size of the bolts used to retai
236. drive the output shaft at a speed reduction shown in paragraph 1 Copyright 1983 General Motors Corp 2 31 HT 740D HT 750D AUTOMATIC TRANSMISSIONS LOCKUP CLUTCH TORQUE CONVERTER 3 THIRD mie TEM FORWARD fa cuh FORWARD CLUTCH PISTON dne PUO i FOURTH CLUTCH P STON MED THIRD CLUTCH PISTON FOURTH CLUTCH SECOND CLUTCH FIRST CLUTCH LOW CLUTCH OUTPUT SHAFT REAR PLANETARY CARRIER CENTER PLANETARY CARRIER FRONT PLANETARY CARS IER SECOND CLUTCH PISTON Eat CLUTCH APPLIED 9 TORQUE PATH 52962 Fig 2 10 Second gear torque path HT 750CRD HT 754CRD e Second G e a Operation fig 2 10 Engine torque is transmitted through the torque converter as described in a above The forward and first clutches are applied The first clutch application anchors the rear planetary ring gear against rotation The forward clutch application locks the turbine shaft and transmission main shaft together so that they rotate as a unit The rear sun gear and low sun g e a r are splined to the main shaft and rotate with it and in turn they rotate the rear and low planetary pin ions respectively With the rear planetary ring gear held stationary by the applied first clutch the rear carrier will rotate in a clockwise direction Since the rear carrier hub is splined to the low carrier ring gear it will also rotate clockwise Since
237. ds b Other Approved Fluids Ford Motor Company specifies fluids M2C33 F M2C138 CJ and M2C166H may be used and may be intermixed with Dexron II fluid c Cold Weather Start up Listed below are the minimum fluid temperatures at which transmission may be safely operated in a forward or reverse range When ambient temperature is below the minimum fluid temperature limit and the transmission is cold preheat is required lf auxiliary heating equipment is available preheat the fluid to the minimum temperature limit If auxiliary heating equipment is not available run the engine for at least 20 minutes with the transmission in neutral before operating in a forward or reverse range Failure to observe the minimum fluid temperature limit can result in transmission malfunction or reduced transmission life Minimum Fluid Fluid Type Temperature Dexron Il or Dexron Type C 3 SAE 10W Type C 3 SAE 30 30 F 34 C 10 F 12 C 32 0F 0 C 3 6 CHANGING THE OIL AND FILTERS a Cleanliness 1 Oil must be handled in clean containers to prevent foreign material entering the transmission CAUTION Containers or fillers that have been used for antifreeze or engine coolant solution must not be used for transmission oil 2 Clean around the oil filler tube before removing the dipstick and lay the dipstick in a clean place while filling the transmission 3 Check the current issue of the HT 700 Series Parts Catalog SA 1268 for p
238. e yellow stripe No Color Code Solid yellow blue stripe No Coils 8 12 Table 8 2 SPRING DATA cont Wire dia 1n mm 0 044 1 12 0 048 1 22 0 049 1 24 0 049 1 24 0 049 1 24 0 049 1 24 0 020 0 050 0 054 1 37 0 020 0 050 0 054 1 37 0 062 1 57 0 054 1 37 0 054 1 37 0 054 1 37 056 1 42 0 054 1 37 Copyright 1983 General Motors Corp Spring OD 1n mm 0 400 10 2 0 409 10 4 0 409 10 4 0 409 10 4 0 409 10 4 0 409 10 4 0 330 8 38 0 640 16 3 0 330 8 38 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 640 16 3 0 410 10 4 0 640 16 3 Free Length 1n mm 1 91 48 5 1 68 42 7 1 79 45 5 1 92 48 8 1 88 47 8 1 93 49 0 1 25 31 8 1 82 46 2 1 25 31 8 2 17 55 1 2 15 54 6 2 50 63 5 2 39 60 7 2 22 56 4 1 63 41 4 2 32 58 9 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 0 94 23 9 1 15 29 2 0 94 23 9 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 15 29 2 1 19 30 2 1 15 29 2 Length Under Load 1n mm Ib N 7 46 to 7 76 33 2 to 34 5 5 14 to 5 36 22 9 to 23 8 8 55 to 9 05 38 0 to 40 3 10 25 to 10 75 45 6 to 47 8 9 75 to 10 25 43 4 to 45 6 9 00 to 9 60 40 0 to 42 7 0 166 to 0 206 0 74 to 0 92 3 5 to 4 25 16 7 to 18 9 0 166 to 0 206 0 74 to 0 9
239. e forward clutch it produces second gear 3 In the HT 750DRD the first clutch has a dual function When engaged with the forward clutch it produces second gear When engaged with the fourth clutch it produces reverse b Description The first clutch in all models contain thirteen clutch plates and a piston Six are internal splined clutch plates and seven are external tanged clutch plates The external tanged plates are held stationary by the transmission housing while the internal splined plates are free to rotate The piston for each model is positioned in its respective bore and retained there by return springs and a spring retainer C Operation A foldout 18 HT 7400 HT 747D 1 When the first clutch is released internal splined plates 2 are free to rotate Since rear planetary ring gear 4 is splined to the internal plates it will also rotate freely 2 When hyaraulic pressure is directed to the back side of the piston shown in phantom the piston compresses clutch plates 1 and 2 together This locks rotating internal splined plates 2 t o stationary external tanged plate 1 preventing ring gear 4 from rotating 3 With the application of forward or fourth clutch in conjunction with the first clutch refer to a 1 above a reaction within the planetary gearing will produce either forward or reverse rotation at the output shaft d Operation A foldout 18 HT 750CRD HT 754CRD 1 Refer to c 1 above
240. e TES coU PRSE END ME BOLT M CARNE C BOLT 144 20 02 10 SEPARATOR Ly ferta PLATE 53785 Fig 7 55 Control valve body bolt locations LOCKUP CUTOFI LC 2 Fa me ML T VALVE EN AM B BOLT L 4 2 X Ins SEEN CR QU am 1 ips 5 1 P f l Yi EA Td Fig 7 56 Installing lockup cutoff valve HT 750 NOTE Some transmissions use cover plate 23 B foldout 16 retained by eight 14 20 x 2 inch bolts 24 instead of the lockup shift valve body assembly Copyright 1983 General Motors Corp 7 30 ASSEMBLY OF TRANSMISSION P BOLT A UE AL Ia LOCKUP CUTOFF VALVE BODY 4 SIGNAL TUBE poteris PEERS a a DE r6 ime et Le 3 ER FEED E pis TE 5 5 Tur E teak ME ud Xr Al rtm pu CT 18 md a 7 i LOW TRIMMER VALVE BODY Low SHIFT MN VALVE BODY Barra Fig 7 58 Installing signal tube HT 750 Fig 7 57 Valve body assemblies HT 750 7 18 INSTALLING FLYWHEEL LOCKUP CLUTCH TORQUE CONVERTER TURBINE 7 Install the low shift valve body onto the lower guide screw fig 7 58 Retain the body with a Align Flywheel for Installation one 1 4 20 x 2 3 4 inch bolt u 1 Position the transmission horizontally 8 Install t h e low trimmer valve 7 59 Install six 1 4
241. e in or the following shift sequence table contact Detroit Diesel Allison Service Department 2 6 TORQUE CONVERTER HOUSING Converter housing 16 B foldout_10 i s machined from cast aluminum The front of the housing is machined to mate with an SAE 1 engine flywheel housing The rear of the housing is machined to accept either retarder plate assembly 2 or 19 BJ foldout 12 or front support and valve assembly 1 or 33 A foldout 13 and transmission housing Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS assembly 7 B foldout 16 The converter housing encloses and supports the torque converter elements and input driven oil pump assembly 1 Bj foldout 10 2 HYDRAULIC RETARDER a The hydraulic retarder B foldout 12 located between the converter and the range gearing consists of three main elements a rotor and two stators The rotor assembly 10 is a vaned member splined to the turbine output shaft The front and rear stators consist of vanes cast into the walls on each side of the retarder rotor b The rotor turns continuously at turbine output shaft soeed However the retarder functions only when the cavity around the rotor is filled with oil A manual valve directs oil which fills the cavity when retarder operation is desired The churning of the oil between the rotor and stators resists the rotation of the rotor Part of this energy is used to circulate the oil through a cool
242. e oil filter sealing and on later models oil filter spacer 32 B foldout 16 Copyright 1983 General Motors Corp 5 5 HT 740D HT 750D AUTOMATIC TRANSMISSIONS b Valve Body 1 Remove the eight bolts that retain the cover plate fig 5 10 or lockup cutoff valve 28 A foldout 21 Remove the plate or valve Refer td para 6 9 for rebuild of the lockup clutch cutoff valve body assembly Remove seven bolts from the separator plate fig 5 10 Remove eighteen bolts from the control valve body Remove one 2 1 2 inch long bolt that retains the selector detent assembly Remove selector detent assembly NOTE Do not attempt to remove the valve body at this time Three bolts located on the underside of the transfer plate fig 6 18 hold the modulator body oil transfer plate separator plate and control valve b o d y together 5 Install two 1 4 20 guide bolts J 24315 3 one at the top the other at the bottom of the oil transfer plate CAUTION Do not allow the selector valve to drop out of the valve body when the assembly is removed Wire it in place or remove it from the valve body 6 Remove the four bolts two washers and baffle that retain the valve body assembly to the transmission Hemove the valve body assembly 7 Refer to paragraph 6 6 for rebuild of the control valve body assembly Fig 5 11 Removing control valve assembly HT 740D 747D 5 7 REMOVING O
243. e outer race of the idler gear bearing is removable On later models the inner race is removable 11 On early models install the outer race chamfered end last into the idler gear bearing bore Snug the race to the snapring Install the inner race and roller bearing into the outer race 12 On later models install the outer race and roller bearing into the idler gear bearing bore Snug the bearing to the snapring Install the inner race chamfered end first 13 Install the transfer idler gear assembly over the spacer if used and align it and the spacer with the spindle bore in the transfer housing fig 6 98 14 Install the chilled idler gear spindle aligning the circular milled slot in the spindle with the lock bolt hole in the transfer housing Seat the spindle in the housing fig 6 98 15 Install the idler spindle retaining washer 6 A ifoldout 22 lockwasher 5 and 7 15 14 x 1 inch bolt 4 Tighten the bolt to 42 to 50 Ib ft 57 to 68 Nem 16 Install the transfer drive gear with bearings attached Tap it into the bearing bore with a soft hammer fig 6 99 Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS TRANSFER HOUSING ij Ee DRANSFER IDLER 51119 Fig 6 98 Installing transfer idler gear spindle 17 If plugs 5 or 7 B foldout 22 were removed re install the plugs If cup plug 9 was used and was removed press a new cup to the bottom of its bore
244. e piston sealrings CLUTCH SLIPPAGE IN FIRST GEAR ONLY HT 750DRD Low clutch slipping 1 Rebuild clutch and replace piston sealrings AB VEHICLE MOVES IN NEUTRAL Range selector linkage out of 1 Adjust linkage properly adjustment Forward clutch will not release 2 Rebuild forward clutch Fourth clutch will not release 3 Rebuild fourth clutch AC c OIL THROWN FROM FILLER TUBE Dipstick loose Oil level too high Breather clogged Dipstick gasket worn Improper dipstick marking high oil level Tighten cap replace if necessar Drain oil to proper level Clean or replace breather Replace gasket or dipstick Replace dipstick EISE I Copyright 1983 General Motors Corp 3 25 3 26 Section 4 GENERAL OVERHAUL INFORMATION 4 1 SCOPE T h i s section provides information required before proceeding with overhaul of the transmission Tools and equipment for overhaul are discussed Information on replacement parts and service kits is provided The importance of cleanliness and careful handling is stressed Helpful information on cleaning and inspection is given General information on the removal and installation of the transmission is given Torque specifications for bolts and nuts are tabulated Information on wear limits and spring specifications is referenced 4 2 TOOLS AND EQUIPMENT a Improvised Tools and Equipment The following items may be improvised e Work table 1500 pound 680 kg capacity fia
245. e retaining nut 31 A foldout 20 to 600 to 800 Ib ft 814 to 1085 Nem Refer tol paragraph 3 14 16 Install the speedometer drive components fig 6 72 6 27 TRANSMISSION HOUSING a Disassembly B foldout 16 1 To remove the manual detent lever use the following procedure Remove the retainer pin and locknut fig 6 83 2 Hold the detent lever in one hand and remove the manual shift by carefully pulling the shaft through the oil seal in the housing Remove the detent lever CAUTION If the shaft is burred or rough smooth it with crocus cloth or a honing stone before removal to avoid scratching the housing bore 3 Remove oil seal 51 B foldout 16 from the transmission housing 4 If replacement of breather 1 is necessary remove it from the housing 5 Inspect neutral safety switch plug 50 washer 49 and reverse signal plug 4 for damage f damaged replace with new parts 6 If it is necessary to replace name plate 6 remove one drive screw 5 NOTE All replacement parts ordered refer to the information on the nameplate Therefore it is imperative that the new nameplate be stamped with identical information RETAINER PIN 0000 MANUAL SHARD P EVER SELECTOR VALVE PIN _ guia ig 6 83 Manual shaft components 204 Fig 6 84 Installing manual shaft oil seal NOTE Refer to above b Assembly Bj foldout 16 1 Coat the inside diameter of oil seal 51 B with a seal lu
246. e seal and cover bore before again attempting installation 7 Remove the seal protector springs fig 6 75 Install the Install thirty PISTON i n CONV ER Seyh Fig 6 79 Installing piston into rear cover spring retainer cupped side first onto the springs 8 Using compressor components J 24204 1 and J 24204 2 compress the retainer and springs 6 75 Install the snapring and remove the compressor 9 If the orifice plug was removed from the output shaft install a new plug orificed side first Use installer J 24369 to properly position the plug in the shaft In each model the plug must clear the chamfer at the front of the plug bore in the output shaft 10 If the bushing was removed from the front of the output shaft install a new bushing fig 6 81 In models HT 740D 747D HT 750CRD 754CRD locate the bushing in the shaft with installer J 24203 Locate the HT 750DRD bushing with installer J 24769 In the HT 740D 747D or HT 750CRD 754CRD the bushing is 0 145 to 0 165 inch 3 68 to 4 19 mm from the front of the shaft In the HT 750DRD the bushing is 0 330 to 0 350 8 38 to 8 89 mm from the front of the shaft 11 Press the speedometer drive gear spacer sleeve and bearing onto the rear output shaft 74 Install the assembled shaft 12 On assemblies before S N 5660 the bevelled snapring bevel toward install Copyright 1983 General Motors Corp 6 54 REBUILD OF SUBASSEMIBLIE
247. ear output shaft fig 6 96 7 On models having a front output disconnect install the drive coupling and snapring onto the output shaft fig 6 97 Install the gasket and adapter Install six 1 2 13 x 1 1 4 inch bolts and lockwashers to retain the adapter Tighten the bolts to 67 to 80 Ib ft 91 to 108 Nem to seat the bearing Copyright 1983 General Motors Corp Tug rn b AN zi ndun zu Me pios sae hy by M ione F HOUSING BRAKE DRUM 51116 Fig 6 96 Installing output shaft front bearing SNAPRING DRIVE COUPLING 81117 Fig 6 97 retaining bolt Installing adapter 8 On models with a front mounted parking brake follow the instructions in 3 and 4 above Then install spacer 28 9 On models which have no front output install gasket 4 B foldout 22 and either cover 3 retained with 2 and eight 1 2 13 x 1 1 4 inch bolts 1 or cover 17 retained by washers 18 and eight 1 2 13 x 1 1 4 inch bolts 19 Tighten the bolts to 67 to ARAS ANE SUBASSEMBLIES 80 Ib ft 91 to 108 Nem When a speedometer drive is included assemble and install items 20 through 28 Tighten the two 5 16 18 x 7 8 inch bolts 28 to 10 to 13 Ib ft 13 6 to 17 6 N m CAUTION Incorrect installation of idler gear bearings 8 and 12 A foldout 22 will cause the bearings to fail 10 Install snapring 9 foldout 22 into its bore in idler gear 10 NOTE On earlier models th
248. ear Unit Second Clutch 7 12 Center Support 7 12 7 9 INSTALLING REAR COMPONENTS HT 750DRD DRD DB a b First Clutch and Ring A Adapter Housing Low Clutch and Planetary E Rear Cover Assembly Temporary Installation of Transfer Gear Housing Adapter Assembly 7 16 INSTALLING GEAR UNIT SECOND CLUTCH CENTER SUPPORT HT 750DRD DRD DB a Gear Unit Second Clutch b Center 7 17 Copyright 1983 General Motors Corp Page Paragraph Page 11 INSTALLING THIRD FOURTH FORWARD CLUTCHES a Third Clutch Fourth S Tio eo 7 18 Db Forward usciti tro qid 7 19 7 12 INSTALLING TORQUE CONVERTER HOUSING models without retarder a Housing With 2 Bolt Top 7 19 b Housing With 8 Bolt Top 07 7 21 7 13 INSTALLING HYDRAULIC RETARDER COMPONENTS a Housing Front Support LE b Rotor Components 7 24 7 14 INSTALLING TORQUE CONVERTER HOUSING models with retarder a Housing With 2 Bolt Top CON GM b Housing With 8 Bolt Top 97 7 24 7 15 INSTALLING TORQUE CONVERTER PUMP STATOR ASSEMBLIES a Pump Assembly
249. ecessary collapse bushing 16 at its seam using a small half round chisel Be careful not to damage the support bore Copyright 1983 General Motors Corp 6 36 REBUILD OF SUBASSEMBLIES NOTE Refer to above b Assembly B foldout 14 1 Place center support 17 on a press hub side up Using bushing installer tool J 28525 2 install a prebored bushing as shown in figure 6 54 Be sure the oil hole in bushing 16 is in proper alignment with the oil hole in center support 17 Swage bushing using swaging tool J 28525 1 andifigure 6 55 as a guide 2 Temporarily place piston 9 in the front piston cavity of center support housing 17 Install twenty springs 8 into the pockets of the piston Align spring retainer 7 on the four ejector pin bosses of the piston Compress the springs by forcing the retainer into the recess at the outer edge of the center support when the retainer rings are installed fig 6 56 Install a new self locking retainer ring 6 on the ejector pins of each piston using installer J 24453 Remove the piston from the center support 53308 Fig 6 54 Installing center support bushing 3 Repeat the procedures in 2 above to assemble items 20 through 23 Bj foldout 14 into the rear cavity to support housing 17 NOTE Force the pistons to the bottom of their cavities during installation of the self locking retainer rings 6 and 23 This will ensure proper clutch clearance 4 Grease with oil soluble
250. ed the impact Is increased and the torque directed through the turbine shaft can exceed the engine torque by an amount equal to the torque ratio of the converter Converter operation is illustrated in first second third and reverse operation where it is most likely to occur b Lockup Operation Power is transmitted mechanically through t h e lockup clutch Application of t h e lockup clutch occurs automatically in selected ranges as a function of governor pressure When the lockup clutch is applied t h e converter elements rotate as a unit at engine speed This provides a direct drive from the engine to the turbine shaft Lockup operation is illustrated in fourth and fifth gear operation Neutral Operation fig 2 15 Engine torque is transmitted through t h e torque converter as described in a above The forward clutch is not engaged Thus torque is not transmitted beyond t h e fourth clutch hub Although the first clutch is applied two clutches must be applied to produce output shaft rotation in either forward or reverse Copyright 1983 General Motors Corp 2 37 HT 740D HT 750D AUTOMATIC TRANSMISSIONS LOCKUP CLUTCH TORQUE CONVERTER FOURTH CLUTCH THIRD CLUTCH FORWARD CLUTCH over ra FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON SECOND CLUTCH FIRST CLUTCH r LOW CLUTCH zu ds O1 Poa LOW PISTON LOW PLANETARY CARRIER
251. ed through the oil passages in the center support to the back side of clutch piston 9 clutch plates and 4 are compressed together This locks the fourth clutch housing to the transmission housing which prevents the fourth clutch housing and attached components from rotation 2 With the application of the forward clutch in conjunction with third clutch a reaction within the planetary gearing will produce a forward rotation to t h e output shaft d Operation of Second Clutch Bj foldout 14 All models 1 When hydraulic pressure is directed through the oil passages in the center support to the front side of clutch piston 20 the piston and clutch plates 25 and 26 are compressed together This locks the front planetary carrier to the transmission housing which prevents the carrier from rotating 2 With the application of the forward clutch in conjunction with the second clutch a reaction within the planetary gearing will produce a forward rotation to the output shaft Copyright 1983 General Motors Corp 2 7 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 2 14 FIRST CLUTCH Ai foldout 18 a Function Differs Among Models 1 The first clutch in the HT 740D and HT 747D has ad u 1 function When engaged simultaneously with the forward clutch it produces first gear When engaged with the fourth clutch it produces reverse gear 2 Inthe HT 750CRD a n d HT 754CRD the first clutch has a single function Engaged with th
252. ed from the date of delivery of the product In question to the original user Jacobs will also pay for all repairs to damaged engine components in which a Jacobs Engine Brake or Jacobs Replacement Parts have been properly installed provided the damage is shown to be a direct result of a defect of the Jacobs Engine Brake or Jacobs Replacement Parts occurring under normal operation during the Warranty Coverage periods specified above This warranty will not apply to any part or parts which have been altered or repaired outside of our factory or authorized Jacobs distributor service centers nor to parts which have been subjected to misuse abuse neglect or accident nor to parts which have been improperly applied or installed Improper installation or application or substitution of parts not manufactured or approved by us shall void this warranty If the product should become defective within the Warranty Coverage period an authorized Jacobs Engine Brake distributor should be notified There is a world wide network of authorized distributors whose names and addresses can be found in the Sales and Service Directory located In the back of your Jacobs Engine Brake Driver s Manual If any of the listed distributors are unable to correct your problem or if you have any questions regarding this warranty write to the following address giving full details of your problem including the Model and Serial Numbers of the product involved WARRANTY ADMINISTRATOR THE JACOBS
253. ed onto the transmission housing Reference para 4 6g and 7 12 6 11 CONVERTER HOUSING WITH 2 BOLT TOP COVER RETARDER PLATE OIL PUMP a Disassembly 1 Refer to para 6 10a 1 through 5 for removal of the oil pump components Note that the oil pump includes two driven gears 2 Remove sealring 1 foldout 12 from the groove in retarder plate 2 3 Remove nineteen bolts retaining the retarder plate fig 6 31 4 Remove the retarder plate and gasket from the converter housing Do not remove the ground sleeve from the retarder plate Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS 7 CONVERTER HOUSING GUIDE SCREW J 24315 1 SEALRING 52931 r Fig 6 30 Installation position of oil pump assembly housing with 2 bolt cover 5 Remove plugs 8 Bj foldout 11 6 Remove studs 7 only if replacement is necessary 7 Remove plug 6 only if replacement is necessary 8 Position the housing rear downward on a clean flat surface 9 Remove lubrication valve pin 13 valve 12 and spring 11 only if parts replacement is necessary NOTE Refer to above b Assembly 1 If lubrication valve components 11 12 and 13 B j foldout 11 were removed install new components Install valve 12 larger end first onto pin 13 Install spring 11 into the valve cavity in the converter housing STUD 12 13 X 12 20 X 6 40131 BOLT 3 8 16 X LOSA E
254. ed to match the snapring colors Select one of the snaprings listed below Select the thickest snapring that can be put into the groove Color code Thickness Blue 0 148 0 150 in 3 76 3 81 mm Yellow 0 152 0 154 in 3 86 3 91 mm White 0 155 0 157 in 3 94 3 99 mm Hed 0 158 0 160 in 4 01 4 06 mm 8 Install the selected snapring to retain the center support Be sure the snapring gap is at the top of the transmission housing regardless of its position when removed 9 sleeve J 24208 2 Remove compressor J 24208 3 and Copyright 1983 General Motors Corp 7 6 ASSEMBLY OF TRANSMISSION c Second Clutch Clearance NOTE Two methods of checking clutch plate clearance have been established One method is by direct measurement as outlined in items c 6 below The alternate method is by stack dimension computation outlined in paragraph 6 33 If the stack method is used to select second clutch components disregard 1 through 6 below 1 Invert the transmission housing rear cover upward 2 Remove the six bolts and washers that temporarily retained the rear cover to the transmission housing Remove the rear cover and gasket Refer to figure 7 8 3 Remove the thirteen low clutch plates from the adapter housing Refer td figure 7 18 Since these plates are preset for the low clutch clearance they should be maintained in a package form so they cannot be intermixed with other plates 4 Re
255. een oolid orange oolid orange oolid green oolid green oolid green Copyright 1983 General Motors Corp No Coils 8 5 8 5 10 2 10 2 11 5 11 5 11 5 8 6 Wire dia in mm 0 054 1 37 0 054 1 37 0 1285 3 26 0 081 2 04 0 092 2 34 0 081 2 04 0 081 2 04 0 081 2 04 0 081 2 04 0 081 2 04 0 062 1 57 0 062 1 57 0 041 1 04 0 041 1 04 0 041 1 04 Spring OD in mm 0 733 18 6 0 733 18 6 0 830 21 1 0 743 18 9 0 743 18 9 0 720 18 3 0 720 18 3 0 720 18 3 0 720 18 3 0 690 17 5 0 439 11 2 0 439 11 2 0 385 9 8 0 385 9 8 0 385 9 8 Free Length in mm 0 81 20 6 1 74 44 2 1 74 44 2 3 94 100 1 3 51 89 1 3 04 77 2 2 66 67 6 2 93 74 4 3 33 84 6 3 22 81 8 2 65 67 3 1 25 31 8 1 25 31 8 1 29 32 8 1 29 32 8 1 29 32 8 0 38 9 7 0 81 20 6 0 81 20 6 2 64 67 1 1 80 45 7 1 80 45 7 1 80 45 7 1 80 45 7 1 80 45 7 1 80 45 7 1 62 41 2 0 88 22 4 0 88 22 4 0 82 20 8 0 82 20 8 0 82 20 8 Length Under Load in mm Ib N 0 36 to 0 66 1 6 to 2 9 5 02 to 6 14 24 3 to 27 3 5 02 to 6 14 24 3 to 27 3 82 4 to 86 6 366 5 to 385 2 39 6 to 42 6 176 1 to 189 5 29 00 to 31 00 129 0 to 137 9 13 44 to 14 36 59 8 to 63 9 17 60 to 18 80 78 3 to 83 6 23 80 to 25 40 105 9 to 113 0
256. efer to para 3 3 for checking oil level 3 20 TROUBLESHOOTING AFTER REMOVAL When the malfunction of a transmission was not detected by tests or inspections before removal from the vehicle the transmission may be mounted in a test stand and checked if a test stand is available Particular attention should be given to proper oil level in every transmission test 3 21 TROUBLESHOOTING The troubleshooting information below outlines the possible causes of transmission troubles and their remedies Capital letters indicate the symptom numerals following the symptom indicate several possible causes corresponding numerals in the right column indicate remedies for the causes Copyright 1983 General Motors Corp 3 17 HT 740D HT 750D AUTOMATIC TRANSMISSIONS JANUARY 1976 PRIOR TO S N 11250 T i AILAN LUBE MAIN FRONT LOCKUP FRONT GOVERNOR GOVERNOR SEPTEMBER 1974 PRIOR TO S N 5940 SEPTEMBER 1974 FOREN 1976 AFTER S N 5939 N 11249 FFE qe Ae MAIN 4 LOCKUP FRONT LUBE GOVERNOR FRONT GOVERNOR 17545 Fig 3 6 Transmission check points without retarder Copyright 1983 General Motors Corp 3 18 PREVENTIVE MAINTENANCE SEPTEMBER 1974 PRIOR TO S N 5940 ai ACTIVE TET rfo 3 SN EFFECTIVE APRIL 1975 AFTER S N 8249 MODULATOR MAIN LOCKUP FRONT GOVERNOR SEPTEMBER 1974 AFTER S N 5939 NOT LUBE NOT ACTIVE
257. emove the fill tube plug and check the oil level The dropbox is full when the oil level is at the top of the fill tube 4 If the dropbox has a dipstick remove it and wipe it clean Insert the dipstick and check the oil level Safe level for the dropbox is any level between the FULL and ADD marks on the dipstick If the oil level is at or below the ADD mark add oil to bring the oil level to midway between the ADD and FULL marks 3 5 HYDRAULIC FLUID RECOMMENDATIONS a Recommended Fluids 1 Hydraulic fluids used in the transmission are important influences on transmission reliability Dexron Dexron Il and type C 3 DDA approved SAE 10W or SAE 30 fluid is the only fluid approved for use in off highway applications Use type C 3 SAE 30 in all applications where the ambient temperature is consistently above 86 F 30 C 2 Some Dexron Il fluids are also qualified as type C 3 fluids and may be used in off highway applications However a Copyright 1983 General Motors Corp 3 3 HT 740D HT 750D AUTOMATIC TRANSMISSIONS Dexron II fluid which is not a qualified type fluid must never be used in off highway applications Consult your local Detroit Diesel Allison dealer or distributor to determine if a Dexron II fluid is also a qualified type C 3 fluid 3 Before using type C 3 fluids consult the vehicle manufacturer to ensure that materials used in tubes hoses external filters seals etc are compatible with C 3 flui
258. enter carrier ring gear in a counterclockwise direction reverse of input This reverse rotation is transferred through the main shaft and the low planetary carrier to the output shaft Thus the transmission output shaft rotates in a reverse direction at a speed reduction shown in paragraph 1 6 Copyright 1983 General Motors Corp 2 36 DESCRIPTION AND OPERATION F LOCKUP CLUTCH TORQUE CONVERTER FOURTH CLUTCH THIRD CLUTCH FORWARD S iii mi CLUTCH FORWARD CLUTCH PISTON ed 6 FOURTH CLUTCH PISTON 7 d THIRD CLUTCH PISTON FIRST Ws SECOND 7 LOW CLUTCH Bi TUE i RE n cd Lig LOW PISTON QUE diis LOW PLANETARY CARRIER FIRST CLUTCH PISTON CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON EM e REAR PLANETARY CARRIER SS CLUTCH APPLIED E TORQUE PATH 92963 Fig 2 15 Neutral torque path HT 750DRD TORQUE PATHS THROUGH TRANSMISSION HT 750DRD 2 34 a Converter Operation Power is transmitted hydraulically through the torque converter The engine drivesthe converter pump The p u m p throws oil against the vanes of the turbine imparting torque to the converter turbine shaft From the turbine oil flows between the vanes of the stator and re enters the pump where the cycle begins again When the engine is idling impact of the oil upon the turbine blades is negligible When the engine is accelerat
259. er gear and spindle n Install the gear and spindle into the bore near the top of the converter housing aligning the bolt hole in the spindle with the tapped hole in the housing 11 Retain the gear and spindle with a 1 2 13 x 3 1 4 inch self locking bolt Tighten the bolt to 81 97 Ib ft 110 131 Nem fig 7 40 12 Install the scavenge pump assembly onto the mounting pad fig 7 41 Through holes in the pump drive gear install three 3 8 16 x 2 1 2 inch bolts with lockwashers to retain the pump Install a 3 8 16 x 7 8 inch self locking bolt to retain the lug on the pump suction tube 13 Tighten the pump mounting bolts to 26 32 Ib ft 35 43 Nem fig 7 41 Tighten the tube lug bolt to 36 43 Ib ft 49 58 Nem 7 13 INSTALLING HYDRAULIC RETARDER COMP ONENTS a Housing Front Support 1 Make sure the thrust race and needle bearing have been installed at the rear of the retarder housing assembly Also check that the needle bearing rear race is in place at the front of the forward clutch fig 7 42 Copyright 1983 General Motors Corp 7 22 ASSEMBLY OF TRANSMISSION J SCAVENGE PUMP ASSEMBLY 1 SUCTION TUBE BOLT 3 8 16 X 7 8 SUCTION TUBE RETAINING CLIP 81768 Fig 7 41 Installing scavenge pump assembly PRETARDER HOUSING Fig 7 42 Installing retarder housing CAUTION Improper installation of the two butt joint sealrings onto the front support hub may cause transmission
260. er to dissipate the heat generated When the control valve is released the retarder cavity is evacuated c The retarder is used to slow the vehicle in traffic on curves or on downgrades Maximum retarder effect occurs in the lowest gear range The throttle should be closed when the retarder is used Long continuous use will raise the oil temperature Short periods of full release to interrupt continuous application will prevent overheating 2 8 OIL PUMP ASSEMBLY a Description B foldout 10 Oil pump assembly 1 consists mainly of three elements drive gear 5 driven gears 8 and pump body 3 The oil pump assembly is retained in the converter housing by six bolts Driven gear or gears 7 is supported in the pump body by gear shafts 6 b Operation foldout 10 When the converter pump rotates its rear hub drives pump drive gear 5 Gear 5 is in mesh with driven gear assembl ies 7 Thus as the gears rotate oil is drawn into the inlet port and is carried between the pump housing and the gear teeth to the outlet side of the pump into the hydraulic system 2 9 FRONT SUPPORT AND VALVE ASSEMBLY The front support and valve assembly is connected to the rear of the retarder housing or to the rear of the converter housing if the unit has no retarder It provides support for the forward clutch and turbine shaft Contained within the support assembly are three valves main pressure regulator valve assembly 3 foldout 13
261. ernal splined low clutch plates from the adapter housing fig 5 54 Copyright 1983 General Motors Corp 5 23 HT 740D HT 750D SERIES TRANSMISSIONS LOW GEAR AND HUB ASSEMBLY LOW CLUTCH PLATES COTTER PIN 1 8 4 REAR PLANETARY RING GEAR im sap j Ma HOUSING 3758 Fig 5 54 Removing low sun gear and hub assembly HT 750DRD 7 Refer paragraph 6 23 for rebuild of the low planetary carrier assembly 8 Remove the adapter housing and gasket a 3 Refer tolparaoraph 6 25 lor rebuild of the adapter housing assembly d First Clutch and Ring Gear 1 Remove the1 8 inch cotter pins from the rear planetary ring gear fig 5 54 2 Grasp the ring gear internally and lift upward removing the ring gear and ten clutch plates from the transmission housing fig 5 56 3 Remove the three remaining clutch 4 Refer to paragraph 6 27 for rebuild of transmission housing assembly plates TRANSMISSION ES HOUSING aT z 57994 Fig 5 55 Removing adapter housing HT 750DRD EE RINGGEAR m AN iy Ct 0 Ted 1 1 b m CLUTCH PLAT eamm CLUTCH 32995 Fig 5 56 Removing rear planetary ring gear HT 750DRD Copyright 1983 General Motors Corp Section 6 REBUILD OF SUBASSEMBLIES 6 1 SCOPE This section describes the disassembly and assembly of subassemblies that were removed in For rebuild procedures refer to the exploded vi
262. ews foldouts 9 through 23 located at the end of this manual Reference is also made to line drawings and photographs in this section 6 2 GENERAL INFORMATION FOR SUBASSEMBLY REBUILD a Tools Parts Methods Refer to paragraphs 4 2 4 3 and 4 4 b Cleaning Inspection Refer t paragraph 4 5 for cleaning and inspection procedures c Torque Specifications The specific torque value for each threaded fastener is stated at each assembly step Torque values are also presented on the foldout illustration d Wear Limits Spring Data Refer to for wear limits and spring data e Plugs and Fittings Prior to installation refer to f Clutch Pack Procedure Clutch clearance must be established prior to assembly Soak the friction faced clutch plates in transmission fluid for two minutes after establishing clutch clearance and prior to assembly g Sleeve Retaining Compound use of Loctite Sleeve Retainer 601 or equivalent is recommended for installing press fit bushings and sleeve type bearings 6 3 FLYWHEEL LOCKUP CLUTCH CONVERTER TURBINE a Disassembly A foldout 9 1 Position the flywheel assembly front downward on the work table fig 6 1 52911 Fig 6 1 Removing converter turbine from flywheel BACK PLATE gt ANCR c courtesy i i STARTER ON RANG GEAR aj Vis ix ate i m A i L DES b la in i
263. f affected components Spring charts are at the end of immediately preceding foldouts e Alternate Method Using Speedometer Readings 1 When a tachometer is not available for checking shift points the vehicle soeedometer can be used Proceed as outlined in 2 through 4 below 2 Check and record the road speed of the vehicle at which lockup occurs in the HT 750CRD HT 754CRD during operation in 1 hold refer to d 3 above Also check and record the top speeds that can be attained while operating in 1 2 2 3 and 3 4 ranges HT 750 only 3 For checking t h e shift points place the selector at 1 4 HT 740D 747D 1 5 HT 750CRD 754CRD or 2 5 HT 750DRD so that all automatic shifts can occur Drive the vehicle at full throttle from a standing start until the 3 4 HT 740 or 4 5 HT 750 upshift occurs Record the road speed at which each upshift occurs 4 Compare the upshift speeds with the speeds recorded in 2 above The 1 2 shift in HT 750CRD 754CRD should occur at approximately two mph below the speed recorded for lockup engagement All other upshifts should occur approximately two mph below the top speeds recorded in 2 above f Calibration by Test Stand Method 1 Ihe shift point check table provides information required for adjusting shift points on transmissions matched to engines having governed speeds from 1950 to 2900 rpm 2 The actual adjustment procedures are as outlined in d above However t
264. f the vehicle and its travel path in the event of brake failure or inadequate blocking Do not maintain the stalled condition longer than 30 seconds due to rapid heating the transmission oil CAUTION With the transmission in neutral run the engine at 1200 to 1500 rpm for 2 minutes to cool the oil between tests Do not allow the converter out temperature to exceed 300 F 149 C Keep close check to prevent the engine cooling system from overheating b Procedure CAUTION Do not attempt to stall test the HT 750 754CRD transmission in reverse nor the HT 750DRD in first gear The extremely high torque produced in either of these gears may damage the transmission and or the vehicle drive line 1 Connect a tachometer of known accuracy to the engine Stall the torque converter by locking the transmission output putting the transmission in gear and accelerating the engine to full throttle Note the maximum rpm the engine will attain The speed attained is then compared to the speed specified by the vehicle manufacturer as normal for those conditions This information stall speed may be obtained from your equipment dealer or distributor An engine speed above or below the specified range may indicate a malfunction in the engine or transmission NOTE Temperature altitude engine accessory loss variations etc affect the power input to the converter These conditions may cause the stall speed to vary 150 rpm from
265. f the fuel pi and subsequent engine damage may result Trj ring i necessary insure proper fit into head of oil jumper Back out oil jumper until metal to metal contact Is made with adjacent housing Back off 1 3 turn from contact point to establish working clearance Hold jumper in this position and lock locknut VALVE AND INJECTOR ADJUSTMENT Adjust valves and time Injectors as instructed In Detroit Diesel Maintenance Manual ADJUSTMENT OF ENGINE BRAKE UNITS To prevent engine damage by piston to valve contact the following Instructions must be followed carefully Prior to making slave piston adjustments Insure exhaust valves are closed and injector Is in delivery position A new Slave Piston setting of 059 has been released to provide for an increase In Engine Brake performance on all 71 and 92 Detroit Diesel series engines There are two requirements which must be met before the 059 setting can be used 1 The engine rocker brackets must be the latest style with a larger pad area for better engine brake housing support The new bracket was Introduced on all Detroit Diesel series 71 and 92 engine about November 1977 The part number for this bracket is 5103903 2 The Model 71A 92A engine brake housings P N 007077 and 007078 only can be used for the new 059 setting Refer to Jacobs Service Letter 160 for differences in engine brake housings Do not use the 059 setting with the former Detroit Diesel Rocker brackets or with
266. fixture with snapring 26 over the ground sleeve Open the safety guards to position the snapring fig 7 48 54104 Fig 7 48 Removing installing converter pump 6 Close the jaws and set the snapring in Copyright 1983 General Motors Corp its bore In the ground sleeve Remove the tool ASSEMBLY OF TRANSMISSION NOTE s madii A If special tool 4J 26598 is not iei MUN 7 man available install the snapring with cia ES snapring pliers Do not scrape the Eu 3 4 ground sleeve splines during rage q M Seren installation 5 HEADLES IDE EP 3 7 On models that do not include an m T engine driven power takeoff install sealring 32 A E i foldout 10 near the outer bolt holes of the pump 5 77 48 Se pe rp IM b Stator Assembly P k i 1 Install the freewheel roller race and E T 3 stator assembly as rebuilt in paragraph 6 4 m el FL aga 2 Rotate the stator clockwise to check A v MEME n UO for freedom of rotation The stator should lock if uni counterclockwise rotation is attempted rele i i x 7 16 INSTALLING VALVE BODY OIL FILTER OIL PAN HT 740D HT 747D hk E LM CU EAE 5138H Fig 7 49 Installing control valve assembly a Valve Body 1 Install two 1 4 20 x 5 inch guide screws J 24315 3 into opposite holes in the bottom of T ND SES the transmission housing fig 7 49 um CAUTION I2 x12 4 Do not allow the selector valve t
267. fluid coupling 6 Thus as explained in 1 through 5 preceding the torque converter accomplishes three main functions It acts as a disconnect clutch because little torque is transmitted at engine idle speed multiplies torque at low turbine high pump speed to give greater starting or driving effort when needed It acts as a fluid coupling to efficiently transmit engine torque to the transmission gearing during drive other than idle or starting 2 5 LOCKUP CLUTCH a Description foldout 10 The lockup clutch consists mainly of three elements piston 3 clutch plate 4 and back plate 5 These elements are located inside the flywheel The piston and backplate rotate with the converter pump The clutch plate is located between the piston and backplate and is splined to the converter turbine b Operation foldout 10 The lockup shift valve directs clutch apply pressure to the lockup clutch piston when sufficient rotational speed is achieved by the forward clutch and turbine shaft assembly The clutch apply pressure compresses the lockup clutch plate between the piston and backplate locking all three together Thus the Copyright 1983 General Motors Corp 2 2 DESCRIPTION AND OPERATION Automatic Shift Sequence and Lockup Converter Designation Transmission Designation Automatic Shift Sequence Lockup Operation Full Throttle Applicable Engine Vocation Standard HI 740D HT 747D 1C 2C 2L 3L
268. foldout 22 in dry ice for one hour before installing it into the transfer gear housing 1 Place the housing rear side down and install the transfer driven gear with its long hub end toward the rear of the housing fig 6 92 NOTE HT 740D HT 750D SERIES TRANSMISSIONS When only a rear output is used the iA iau hub of the drive gear eem Fig 6 92 Installing transfer driven gear must be toward the front of the transfer housing 2 Carefully turn the housing front side down loose gear inside Align the gear with the bearing bores in he bottom of the housing and install the output shaft spacer toward the gear fig 6 93 NOTE If a rear output disconnect assembly Is used disregard 3 and 4 below Continue with 5 below If there is no front output continue with 9 below 3 If the baffle oil seal and oil drain tube were removed install them into the retainer 6 94 Before Installing the liptype seal refer to paragraph 4 6 for seal preparation The oil drain tube must align with the bottom of the chamfer in the hole into which it fits The oil seal is installed lip first and pressed lightly against the shoulder in the retainer The baffle is installed flat side first as shown flush with the rear of the retainer Install the retainer gasket and retainer assembly Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS OUTPUT SHAFT BALL BEA
269. four of the six bolts retaining the oil pump assembly Loosen the remaining two bolts leaving about four turns of thread engaged 3 Press on the wood 2 x 4 51 x 102 mm and tap alternately on the two loose bolts fig 6 23 This will dislodge the oil pump Remove the two remaining bolts and allow the pump to drop onto the wood support Remove the pump assembly Remove the sealring if present from the outer circumference of the pump Remove the screw that retains the 4 cover to the oil pump body fig 6 24 Remove the cover sealring if used and the oil pump body containing the drive gear and driven gear assembly lf any of the 3 4 inch plugs used in later models in the oil pump body are damaged replace them with new plugs 5 Remove the roller bearing from the driven gear and the oil seal from the pump assembly Copyright 1983 General Motors Corp 6 17 HT 740D HT 750D SERIES TRANSMISSIONS 52025 Fig 6 23 Supporting oil pump during removal WARNING The main pressure regulator valve spring is under approximately 85 Ibs 378 N compression 6 Using spring compressor J 24219 depress the main pressure regulator valve spring 6 25 25 Remove the snapring NOTE The spring compressor may be used whether the front support assembly is attached to or removed from the torque converter housing 7 Remove the spring compressor and remove washer 6 Aj foldout 13 valve stop 5 spring 4
270. g 6 2 9 Install the lockup clutch back plate flat side first engaging the notch in the plate with the key in the flywheel ig 62 10 If ball bearing 6 A foldout 10 was removed press it onto the hub of turbine 7 11 Carefully center t h e lockup clutch plate in the flywheel Install the torque converter turbine engaging its hub splines with the internal splines of the lockup clutch plate Seat the ball bearing in its bore 6 4 TORQUE CONVERTER STATOR ASSEMBLY a Disassembly A foldout 10 1 Rotate stator freewheel roller race 25 in a clockwise direction to free it for removal 2 Remove race 25 thrust bearing 24 thrust bearing race 23 ten stator rollers 22 and ten freewheel roller springs 21 from stator assembly 13 NOTE Refer to above b Rebuilding Stator Assembly A foldout 10 NOTE Do not disassemble the stator assembly unless replacement of stator thrust washer 14 rivets 19 or washer 18 is necessary If stator 16 or cam 17 is cracked or damaged replace the complete stator assembly A hydraulic press having a minimum capacity of five tons an adjustable table and a pressure gauge to assist in determining the rivet staking load that is required to rebuild the stator assembly 1 Place the stator assembly in a drill press formed rivet side up fig 6 10 2 Using a 3 8 inch drill align and drill the rivet removing the formed head 3 Place base plate J 29121 2 under the stator a
271. g 7 50 Install the selector detent and retain it M ec HOLS IAG with one 1 4 20 x 2 1 2 inch bolt G 6 Install the cover plate and retain it with eight 1 4 20 x 2 inch bolts marked E fig 7 50 Some transmissions use Ju cutoff valve assembly 28 A foldout W ue Let M 21 If used install this valve JM 51990 assembly instead of the cover plate Fig 7 51 Installing oil filter in 6 above Retain it with eight 1 4 MN 1 Install the sealring onto the oil intake 7 Install seven 1 4 20 x 1 1 2 inch bolts ome marked F the separator plate transfer plate pipe fig 7 51 Lubricate the sealring with oil soluble and into the transmission housing Hives 2 Install the oil filter making sure the 8 M Hold the detent in alignment over the fig ZS detent lever while the 2 1 2 inch bolt is tightened to 9 11 intake pipe fits snugly into the housing fig 7 90 Do lb ft 12 15 N m Tighten all 38 of the bolts to 9 11 Ib not twist the oil filter during installation push straight ft 12 15 N m inward 9 On models that include a lockup NOTE cutoff valve see note following 6 above install the signal tube as shown in figure 7 58 Six seven and eight and one half inch deep oil pans are available for CAUTION the transmission Each pan requires a different oil filter and each filter is The front end of the tube must be retained to the transmission installed int
272. g 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN FIRST AND REVERSE GEARS ONLY HT 750CRD Low clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN FIFTH AND REVERSE GEARS ONLY HT 750CRD DRD Fourth clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN ALL FORWARD GEARS BUT NO SLIPPAGE IN REVERSE all models Forward clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN FOURTH AND REVERSE GEARS ONLY HT 740D Fourth clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN THIRD GEAR ONLY HT 740D Third clutch slipping 1 Rebuild clutch and replace piston sealrings Copyright 1983 General Motors Corp 3 24 I lt i gt lt I lt IN PREVENTIVE MAINTENANCE Table 3 1 TROUBLESHOOTING CHART cont Cause Remedy CLUTCH SLIPPAGE IN SECOND GEAR ONLY HT 740D Second clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN FOURTH GEAR ONLY HT 750CRD DRD Third clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN THIRD GEAR ONLY HT 750CRD DRD Second clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN SECOND GEAR ONLY HT 750CRD First clutch slipping 1 Rebuild clutch and replace piston sealrings CLUTCH SLIPPAGE IN SECOND AND REVERSE GEARS ONLY HT 750DRD First clutch slipping 1 Rebuild clutch and replac
273. g gear fig 5 48 Remove the remaining eleven clutch plates fig 5 48 NOTE Tie the first clutch plates together and identify the pack Retain for Inspection Copyright 1983 General Motors Corp DISASSEMBLY OF TRANSMISSION iuo set Ae LS Ju L 1 sie ee 3 Fig 5 48 Removing first clutch plates HT 750CRD HT 754CRD 5 15 REMOVING CENTER SUPPORT GEAR UNIT SECOND CLUTCH HT 750CRD HT 754CRD a Supporting Gear Unit 1 With the output end of the transmission upward install the adapter housing less piston and gasket 2 Place center support compressor bar J 24208 3 across the rear of the adapter housing so that the center hole in the bar will engage the mainshaft 5 49 3 Install two bolts to retain the tool and the adapter housing to the transmission housing b Removing Components 1 Invert the transmission housing converter end upward Remove the center support anchor bolt and washer figure 5 37 2 Remove the snapring that retains the center support assembly fig 5 38 3 Install center support lifting bracket J 24195 into the recess between the sealrings on the center support hub fig 5 39 Y Lh alike iX 20 n s mre ert Romer E 1 pi NUS D 15 1 via M ju 7 ame rs P eats i roni gr dem sts T AUN kn DE T j Jy
274. gasket 41 pump hub 42 and hub sealring 43 Do not remove ball bearing unless part replacement is necessary 4 On later models remove bolts 27 lockstrips 28 one piece retainer 30 split DL CR ARS aa Buc ES ho SEALRING ie e Fx E d aus US 519565 Fig 6 17 Torque converter pump components race bearing 36 gasket 40 pump hub 42 and hub sealring 43 5 On models containing converter housing PTO gears remove items 27 28 29 and 39 Do not remove bearing 38 unless part replacement is necessary 69 The torque converter must be rebalanced if balance weights 34 were added or replaced NOTE Refer to above b Assembly A foldout 10 NOTE Items 2 through 10 below describe the installation of the split race bearing Items 12 through 15 describe the installation of the PTO drive gear with a double row ball bearing 1 If bearing 36 split race was removed from the converter pump use the following procedure to install a new bearing 2 Make sure the outer races have the same serial numbers and all the bearing balls on the inner race are in place Copyright 1983 General Motors Corp 6 8 REBUILD OF SUBASSEMBLIES 3 Install new bearing 36 all three parts into pump hub 42 4 Place new gasket 40 onto pump hub 42 and install both the gasket and the hub onto the rear of the converter pump 33 5 Install retainer 31 into the front of the converter pump 33 Alig
275. ger Uti aia AM es T Y ed Ek ill 2 CONVERTER ELT ji TURBINE boo E CE CEPT ry een aS T Fig 6 7 Removing rivets from converter turbine 14 Inspect detail lockup clutch drive gear for cracks distortion abrasion battered or broken teeth 14 Reassemble components being sure to correctly index punch marks of the lockup drive gear turbine and hub Use the Copyright 1983 General Motors Corp 6 3 HT 740D HT 750D SERIES TRANSMISSIONS new rivets to help index the detail components 16 Install sixteen new rivets through the turbine turbine hub and lockup clutch gear 6 8 17 Assemble base plate J 29535 1 solid side of plate against the rivet heads fig 6 8 18 Place guide plate J 29535 2 on top of the assembled components Centrally locate the rivets in the holes of the guide plate 19 Retain the turbine assembly and the two plates with bolt 1 2 13 x 3 1 2 fig 6 8 Tighten the bolt 50 Ib ft 68 N m 20 Place the turbine and fixture in the hydraulic press 29 21 Insert staking tool J 29535 5 into the top plate fig 6 9 Using an alternating pattern swage each rivet 22 Remove staking tool retaining bolt guide and base plate NOTE Each reclaimed assembly must be balanced by rotating type static balance to within 1 0 ounce inch by removing metal from area indicated as required maintaining 0 13 minimum wall Optional to drill 0 250 diameter holes thru fo
276. grease and install inner seal ring 10 and 19 and outer sealrings 11 and 18 onto pistons 9 and 20 The lips of all sealrings must be toward the piston cavities of the center support 5 Inspect the piston cavities in center support housing 17 for any obstruction or foreign material Install piston 20 into the rear of the center support Be sure the lips of both the inner and outer sealrings face the bottom of the piston cavity Leave the assembled third clutch piston 9 out of the center support until final installation of the center support assembly in Section 7 6 Lubricate needle roller bearing 13 and bearing race 14 with oil soluble grease Install the race flat side first onto the front hub of the center support To facilitate assembly keep the race square with the support housing hub during installation Forcing may damage the race Install the needle roller bearing onto the race NOTE Do not install butt joint sealrings onto the support hub until the center support and fourth clutch assemblies are installed into the transmission in Reference 7 10b and 7 11a Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS CENTER SUPPORT IDENTIFYING NOTCH OF BUSHING MUST LIE IN THIS AREA SURFACE 500 LB 2224 N MINIMUM ASSEMBLY 2 565 65 15 mm 2 556 65 18 mm PRESS BUSHING FLUSH TOO O10 IN 0 25mm BELOW THIS SURFACE B SWAGE BUSHING S
277. h reverse signal pressure is also directed to the bottom of the 1 2 relay valve The pressure at this point prevents the relay valve from moving downward during reverse operation On later models a bypass and check ball are provided between the reverse and first trimmer passages to ensure rapid charging of the first clutch when a shift is made from first to reverse 5 When the circuits are charged as described for the s h i f t to drive 4 D4 above any forward shift from first to second second to third and third to fourth can occur automatically These shifts occur as a result of r e a r governor pressure At less than full throttle modulator pressure will assist governor pressure 6 Movement of the selector valve determines the highest gear which will be normally reached automatically In drive 4 D4 automatic 1 2 2 3 and 3 4 shifts can Copyright 1983 General Motors Corp 2 19 HT 740D HT 750D AUTOMATIC TRANSMISSIONS occur In drive 3 D3 automatic 1 2 and 2 3 shifts can occur In drive 2 D2 an automatic 1 2 shift can occur In drive 1 D1 no upshift can occur unless overspeed occurs Automatic downshifts can occur within the selected ranges NOTE Models equipped with a second gear start feature will always start in second gear and progress to the highest gear Refer to paragraph 2 24 7 The various drive ranges limit the highest gear attainable by introducing a pressure which prevents rear go
278. h housing fig 6 37 Install fourth clutch driving hub 22 foldout 13 and retain it with snapring 23 27 Grease and install two hook type sealrings 4 B foldout 13 Install hook type seal ring 1 on the front of the turbine shaft Install thrust bearing race 2 cupped side first onto the front of the forward clutch housing 28 Grease with oil soluble grease and install bearing race 24 flat side first and needle bearing 25 onto the rear of forward clutch hub 19 6 18 FOURTH CLUTCH ASSEMBLY a Disassembly A foldout 14 1 Remove the bearing race from the front hub of the fourth clutch housing fig 6 46 2 Remove the bearing race from the rear hub of the fourth clutch housing fig 6 47 FRONT ri j ji HOLIS INE 51969 Fig 6 46 Removing installing fourth clutch front bearing race 3 Place the fourth clutch snapring up on the work table r Hemove the large snapring and the backplate fig 6 48 b Remove f i v e external tanged clutch plates and five internal splined clutch plates 6 Using J 24204 2 and J 24204 3 compress the spring retainer until it is clear of the snapring fig 6 49 Remove the snapring assembly 7 Carefully release t h e pressure from the spring retainer Remove the retainer and twenty piston return springs 8 Remove the piston f r o m the clutch housing E 6 49 9 Remove sealrings 10 and 11 Aj foldout 14 10 Check the
279. he loading pin installing a steel thrust washer at each end of the pinion and installing a bronze thrust washer onto each steel thrust washer NOTE Lubricate the needle rollers and the thrust washers before assembling the pinion groups 6 Position t h e carrier assembly rear end upward except the center carrier Install all pinion groups into the planetary carrier aligning the loading pins see chart with the pin bores in the carrier 7 Install the proper pinion guide pins see chart larger diameters first into the pinion pin bores Push the guide pins through the carrier until the loading pins drop out 8 Position the carrier assembly on the press fixture using the proper pin remover and installed adapter if required 9 Select the proper pin installer and install It into the press fixture ram NOTE Pin installers are shaped to avoid interference with boses on the carrier assemblies They must be Installed in the ram so that the cutaway portion of the installer will clear the bosses when the pinion is pressed in 10 Place a pinion pin onto the pilot end of the pin guide located below the press fixture ram Press the pinion pin into the carrier until the installer contacts the carrier Copyright 1983 General Motors Corp 6 47 HT 740D HT 750D AUTOMATIC TRANSMISSIONS NOTE All tools have a basic number J 25587 and a suffix Only the suffix is shown below The figures In parentheses
280. he base for checks and adjustments is output shaft speeds instead of engine governed speed Individual output shaft speed ranges are given for each shift 3 11 EXTERNAL LINES AND OIL COOLER a External Lines 1 Inspect for loose or leaking connections worn or damaged hoses tubing and loose fastenings 2 Examine the radiator coolant for traces of transmission oil This condition indicates a faulty heat exchanger b Oil Cooler Transmission operation at abnormally high temperatures can cause clogging of the oil cooler as well as transmission failure It is suggested the oil cooler system be thoroughly cleaned after each major or minor rebuild Failure to do so may cause poor performance overheating and transmission damage For recommendations for cleaning or flushing the oil cooler see the vehicle service manual Copyright 1983 General Motors Corp 3 12 PREVENTIVE MAINTENANCE 3 12 TRANSMISSION STALL TEST a Purpose A stall test may be conducted when the power package engine transmission combined is not performing satisfactorily The purpose of the test is to determine whether the transmission or the engine is the malfunctioning component WARNING When conducting a converter stall test the vehicle must be positively prevented from moving Both the parking and service brakes must be applied and if necessary the vehicle should be blocked to prevent movement forward or in reverse Warn personnel to keep clear o
281. his gives direct drive through the transmission 2 19 SPEEDOMETER DRIVE Straight Through Models a Description A foldout 20 1 The speedometer drive consists of drive gear 24 and driven gear bushing 15 2 Drive gear 24 is a w o r m gear with a right hand helix The gear is concentric with the output shaft and has no key or drive splines The drive gear is clamped between rotating parts which in turn cause the drive gear to rotate b Operation A When the transmission output shaft rotates drive gear 24 rotates Bushing 15 supports the driven gear vehicle furnished within the rear cover The driven gear rotates clockwise as viewed at the cable connection in the rear cover during forward operation 2 20 GOVERNOR a Description AJ foldout 20 Governor assembly 38 is a centrifugal flyweight governor which is driven by a gear that is integral with output shaft 23 or 30 The governor is supported by a bore in rear cover 14 and pin 11 and retained in the rear cover by cover 42 b Operation A foldout 20 Rotation of the governor causes the governor valve foldouts 5 6 7 8 to travel within its bore When the valve moves leftward governor Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS pressure rises when the valve moves rightward governor pressure falls Thus governor pressure is proportional to transmission output speed Governor ressure in combination with modulator p
282. ide of the piston fig 6 69 7 Install the piston assembly into the adapter housing being very careful to avoid folding the seal lips back upon themselves If any difficulty is encountered remove the piston and check the seals and housing bore before again attempting installation 6 26 REAR COVER ASSEMBLY a Disassembly Aj foldout 20 1 Using remover tools J 24171 1 2 4 remove the dust shield from the rear cover fig 6 71 2 Using remover tools J 24171 1 2 4 remove the output shaft oil seal from the rear cover 6 72 3 Remove the speedometer components from the rear cover fig 6 72 drive J 24171 2 amp 4 24171 1 52943 Fig 6 71 Removing dust shield from rear cover 4 Remove the snapring that retains the rear output shaft bearing fig 6 73 b Remove the rear output shaft and its attached parts from the rear cover Hig 6 74 6 Support the front of the speedometer drive gear and press the output shaft from the gear spacer sleeve and bearing lig 6 74 7 If orifice plug 20 A foldout 20 or bushing 22 requires replacement in HT 740D 747D or 750DRD remove either or both as required In the HT 750CRD or HT 754CRD the corresponding items are orifice plug 2 and bushing 29 Treat them in the same manner as items 20 and 22 Copyright 1983 General Motors Corp 6 51 HT 740D il seal 52045 Removing or installing output shaft bearing snapr
283. ift signal valve spring 13 Low shift signal valve stop 14 Washer 15 Spring adjusting ring 16 Plug valve HT 750CRD only 17 Bolt 1 4 20 x 4 6 A 18 Low trimmer valve body assembly 19 Low trimmer valve body 20 Retainer pin 21 Low trimmer valve 1 Lockwasher 3 8 4 2 Bolt 3 8 16 x 2 5 8 4 A 3 Lockwasher 3 8 2 4 Bolt 3 8 16 x 3 3 4 2 A 5 Lockwasher 3 8 2 6 Bolt 3 8 16 x 4 3 4 2 A 7 Plug 8 Retarder control valve body gasket 9 Retarder control valve body assembly 10 Oil seal 11 Oil seal 12 Internal snapring 13 Retarder control valve body 22 Low trimmer plug 23 Low trimmer spring secondary 24 Low trimmer spring primary 25 Low trimmer valve stop 26 Low trimmer valve plug 27 Bolt 1 4 20 x 3 8 A 28 Lockup cutoff valve body assembly 29 Lockup cutoff valve body 30 Retainer pin 31 Retainer pin 32 Retainer pin 33 Third and fourth clutch lockup cutoff valve 34 Valve plug 35 Valve plug 36 First and second clutch lockup cutoff valve 3 Second and third clutch lockup cutoff valve 38 Valve plug Torque lb ft Nem A 26 32 12 15 14 Retarder control valve 15 Washer 16 Retarder control valve spring 17 Washer 18 External snapping 19 Retarder control valve cover gasket 20 Retarder control valve cover 21 Lockwasher 3 8 2 22 Bolt 3 16 x 7 8 2 A Torque loft Nem A 26 32 35
284. imeters 15 5 sq inches meter centare 100 sq decimeters 10 76 sq ft dekameter are 100 sq meters 1 076 4 sq feet hectometer hectare 100 sq dekameters 2 47 acres kilometer 100 sq hectometers 386 sq mile Cubic Measure centimeter 1000 cu millimeters 06 cu Inch decimeter 1000 cu centimeters 61 02 cu inches meter 1000 cu decimeters 35 31 cu feet Approximate Conversion Factors To centimeters meters meters kilometers square centimeters square meters square meters square kilometers square hectometers cubic meters cubic meters milliliters liters liters liters grams kilograms metric tons newton meters newton meters Fahrenheit temperature Multiply by 2 540 305 914 1 609 6 451 093 836 2 590 405 028 65 29 573 473 946 3 85 28 349 454 2907 1 356 11296 5 9 after subtracting 32 Temperature Exact To change To Multiply by ounce inches newton meters 007062 centimeters inches 394 meters feet 3 280 meters yards 1 094 kilometers miles 621 square centimeters square inches 155 square meters square feet 10 764 square meters square yards 1 196 square kilometers square miles 386 square hectometers 2 471 cubic meters cubic feet 35 315 cubic meters cubic yards 1 308 milliliters fluid ounces 034 liters pints 2 113 liters quarts 1 057 liters gallons 264 grams ounces 035 kilograms pounds 2 205 metric ton
285. in the transmission These are low clutch first clutch second clutch third clutch fourth clutch and forward clutch The clutches are applied for various conditions as follows Condition Clutch es applied Neutral First First gear Low and forward Second gear First and forward Third gear Second and forward Fourth gear Third and forward Fifth gear Fourth and forward Reverse gear First and fourth 2 Each of the six clutches has its own circuit Each clutch except the forward clutch is connected to a relay valve and a trimmer valve The forward clutch is connected directly to the selector valve and does not require connection to a trimmer valve because the vehicle is not moving 3 The first clutch circuit connects the clutch to the 1 2 relay valve In neutral the 1 2relay valve is held upward by its spring force and main pressure red is directed to the clutch circuit The 2 3 relay valve is also held upward by its spring force and cannot move downward unless the 2 3 Copyright 1983 General Motors Corp 2 21 HT 740D HT 750D AUTOMATIC TRANSMISSIONS signal line is changed This will not occur in neutral vehicle standing because there is no governor pressure to shift the 2 3 signal valve Only the first clutch is applied so the transmission output will not rotate until two clutches are applied simultaneously refer to fig 2 15 4 The first clutch in addition to being applied during neutral operation is also
286. ine Brake solenoids Repeat the above process six to eight times to bleed entrapped air from the Engine Brake housings During the bleeding process the Engine Brakes will begin to react as evidenced by exhaust noise and rapid engine deceleration The engine may die during the above procedure however after the engine lube oil temperature rises to normal the Engine Brake will shut off before the engine dies TEAR DOWN AND REBUILDING OF BRAKE UNIT REMOVAL OF CONTROL VALVE housing assembly To reinstall reverse procedure REMOVAL OF SOLENOID VALVE Insert screw driver into Jacobs solenoid wrench and loosen solenoid Screw out solenoid valve WARNING THE SLAVE PISTON IS RETAINED BY A SPRING OR SPRINGS THAT IS UNDER HEAVY COMPRESSION IF THE FOLLOWING INSTRUCTIONS ARE NOT FOLLOWED AND PROPER TOOLS NOT USED THE SPRING COULD BE DISCHARGED WITH ENOUGH FORCE TO CAUSE PERSONAL INJURY Eu t Invert the housing Use an arbor press or C Lubricate seals with Engine lube oil before assembly clamp to hold the slave piston spring and Insert lower 1083 0 ring in bottom of solenoid bore in retainer in place Remove the snap ring with housing Install upper 1081 0 ring on solenoid valve special snap ring pliers furnished in Jacobs Install center 1082 0 ring on solenoid valve Insert tool kit Slowly back off on the force solenoid into housing gently without disturbing O ring applied to the retainer to relax the slave
287. ined in paragraph 6 33 If the stack method is used disregard items 4 and 5 Copyright 1983 General Motors Corp 7 17 HT 740D HT 750D AUTOMATIC TRANSMISSIONS a Third Clutch Fourth Clutch yr 1 When installing the third clutch plates fig 4 7 32 the external tanged clutch plates must have a e definite tang to slot relation tangs must be installed into the shorter narrower slots the wider slots are longer and extend to the second clutch plates illustrates the proper tang slot relationship note the wider space between two of the tangs and its location 2 Install ten third clutch plates fig 7 32 beginning with a thick external tanged plate and alternately installing five external tanged plates and five internal splined plates Refer HEC WET CAUTION v Be sure the clutch plate next to the piston is a thick plate 3 Install backplate 2 B foldout 14 and white color coded snapring 1 Be sure the gap of the snapring is at the top of the transmission housing regardless of its position when removed 4 Check the third clutch clearance by ell inserting gage J 24193 between the snapring and the backplate of the third clutch fig 7 33 The clearance PORE ANG BESI should be 0 060 0 120 inch 1 52 3 05 mm Any TU dimension between 0 060 0 120 inch is satisfactory However the closer the clearance is to 0 060 inch the Fig 7 32 Installing third clutch plates
288. ing HT 750D AUTOMATIC TRANSMISSIONS Fig 6 74 Removing or installing output shaft 8 Using compressor components J 24204 1 an d J 24204 2 compress the spring retainer and springs fig 6 75 Remove the snapring and remove the compressor 9 Hemove the spring retainer and 30 fig 6 75 10 Remove the clutch piston fig 6 75 Remove the inner and outer sealrings from the piston 11 If the speedometer driven gear bushing requires replacement remove it Thread remover J 24205 2 into the bushing Attach slide hammer J 6125 1 to remover J 24205 2 and remove the bushing 12 Remove any remaining parts dowel pins snapring governor support pin springs Copyright 1983 General Motors Corp 6 52 REBUILD OF SUBASSEMBLIES ne olugs that require replacement from the rear cover ESC 6 76 1 24204 1 NOTE Refer to paragraph 6 2 above b Assembly Al foldout 20 1 If removed replace t h e dowel pins in the mounting face of the rear cover fig 6 75 The dowel pins project 0 360 to 0 400 inch 9 15 to 10 16 mm above the face of the cover NOTE Snapring 18 A required on earlier models 2 If removed install the bearing front si cone de CE snapring into the rear cover fig 6 77 Install plugs if i ME oem fig 6 78 RETA INER DOWEL PIN removed into the rear cover BUSHING 52947 Fig 6 75 Removing installing snapring that retains piston in re
289. ing exploded view Copyright 1983 General motors Corp FOLDOUT 12 1 Front support and valve assembly 2 Front support and ground sleeve assembly 3 Main pressure regulator valve 4 Main regulator valve spring 5 Valve stop 6 Retainer washer 7 Internal snapping 8 Lockup shift valve 9 Valve spring 10 Valve stop 11 Retainer washer 12 Internal snapping 13 Valve spring 14 Converter bypass valve 15 Valve seat 16 Valve support assembly 17 Valve guide 18 Valve support 19 Snapring 20 Roller bearing assembly 21 Bolt 3 8 16 x 2 1 2 3 A 22 Bolt 3 8 16 x 4 6 A 23 Thrust bearing race 24 Roller bearing assembly 25 Butt joint sealring 2 26 locknut 10 32 t2 2 Front pilot blocker 28 Front pilot tube 29 Bolt 3 8 16 x 1 1 2 16 A 30 Sleeve assembly 31 Pin Rework only 32 Sleeve Rework only 33 Front support and sleeve assembly with retarder 34 Bolt 3 8 16 x 5 6 A 35 Bolt 3 816 x 1 1 2716 A Torque Ib ft Nem A 36 3 49 58 B 1 Sealring 2 Thrust bearing race 3 Forward clutch assembly 4 Hook type sealring 2 5 Forward clutch housing and input shaft assembly 6 Pitot collector ring 7 Ball 3 16 4 8 Internal snapping 9 PTO gear 10 Piston inner sealring 11 Piston outer sealring 12 Forward clutch piston marked A 1 110 1 120 THK B 1 137 1 147 1 164 1 174 13 For
290. ing The three studs engage holes in the retarder housing 3 Install two 1 2 13 x 6 1 2 inch bolts with flat washers into the recessed holes in the scavenge pump mounting pad fig 7 45 4 Into the next bolt hole counterclockwise install a 1 2 13 x 6 1 4 inch early models or 6 1 2 inch later models bolt with a lockwasher fig 7 45 b Install a 1 2 13 6 1 4 inch early models or 7 3 4 inch later models b o 1 t with a lockwasher into the hole nearest the side PTO gear spindle fig 7 45 Install three 1 2 13 x 6 1 4 inch bolts with lockwashers into the three remaining holes HOIST LIFTING SLING e UU dog TT gs GUIDE BOLT L ROTOR ASSEMBLY ___ STUD 122 13 x quee 102 20 x 6 40 3 RETARDER HOUSING ME p DLE TRANSMISSION Geile te HOUSING WA E rH SAM BIST ur e dn El A SU Fig 7 44 Installing the converter housing bolts i x 6 Tighten the seven bolts installed in items 3 4 and 5 to 67 80 Ib ft 90 108 Nem 7 Install eight 1 2 13 x 6 inch bolts with lockwashers through the front flange of the transmission housing the retarder housing and into the rear of the converter housing 8 Install three 1 2 inch lockwashers and three 1 2 20 nuts onto the studs projecting through the transmission housing front flange 9 Tighten the eight bolts and the three nuts to 67 80 Ib ft 90 108 Nem 10 For trans
291. install a 0 300 psi 0 2068 kPa gage at the lockup pressure tap During road operation in 1 hold observe the first movement of the gage and note rpm This is first gear lockup engagement speed 3 While driving the vehicle in 1 4 HT 740 or 2 5 HT 750 range check the w i d e open throttle upshift points These shifts should occur at 100 rpm below engine no load governed speed If upshift speed points do not reach those specified the shiftpoint speed may be raised by adjusting increasing the spring load on the 1 2 2 3 Copyright 1983 General Motors Corp 3 11 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 3 4 or 4 5 HT 750 only shift signal valve If upshift speeds are above those engine speeds specified or do not occur at all the spring load s must be reduced Only the load on springs for the valve or valves which do not upshift at the proper speed require adjustment NOTE If more than one shift signal valve spring requires adjustment in the same direction it may be necessary to adjust the spring force on the modulator valve in the same direction If not adjusted the closed throttle downshifts may be abnormally high or low depending on the direction the shift signal adjusting rings were rotated If all full throttle upshift points are too low by approximately the same amount check adjustment on the modulator external linkage 4 Refer to Sections 5 6 and for procedures covering removal and replacement o
292. ion requires replacement of the entire pinion gear set because they are selectively matched b Removal Installation of Pinion Components NOTE The hydraulic press used with J 25587 01 Planetary Rebuilding Set should have a ten ton capacity an adjustable press bed of 25 inch minimum opening and a pressure gage to assist in determining proper installation and staking of the pinion pins 1 Using a drill that is slightly smaller than the pinion pin diameter drill into the swaged ends of the pins only one end required Do not drill into the carrier The rear ends of all pinion pins except those in the center carrier assembly will be drilled Drill the front ends of the center assembly pins 2 Place press fixture 25587 1 in a hydraulic press Select the proper spacer and adapter if required from the tool chart below Position these parts if used to support the carrier assembly drilled ends of pinion pins upward solidly on the press fixture 3 Install the proper pin remover see chart into the ram of the press fixture Press the pinion pins from the carrier assembly 4 Remove the pinion groups consisting of pinions bearings and thrust washers If bushing in the carrier assembly must be replaced refer to c below b Assemble all of the pinion groups for the carrier assembly Each group is assembled by inserting the proper loading pin into the bore of the pinion installing the needle roller bearings around t
293. ion but locks in the opposite direction b Operation 1 The torque converter assembly is continually filled with oil which flows through the converter to cool and lubricate it When the converter is driven by the engine the pump vanes throw oil against the turbine vanes The impact of the oil against the turbine vanes tends to rotate the turbine 2 The turbine splined to the turbine input shaft transmits torque to the transmission gearing At engine idle speed the impact of oil against the turbine vanes is light At high engine speed the impact is much greater than at idle and high torque is produced by the turbine 3 Oil thrown into the turbine flows to the stator vanes The stator vanes change the direction of the oil flow when the stator is locked against rotation and directs the oil to the pump in a direction that assists pump rotation lt is the redirection and velocity of oil to the pump that enables the torque converter to multiply input torque 4 Greatest torque multiplication occurs when the turbine is stalled and the pump is rotating at its highest speed Torque multiplication decreases as the turbine rotates and gains speed 5 When turbine speed approaches the speed of the pump oil flowing to the stator begins striking the backs of the stator vanes This rotates the stator in the same direction as the turbine and pump At this point torque multiplication stops and the converter becomes in effect a
294. isassembly foldout 12 Aj foldout 13 1 Position the retarder housing front support assembly upward fig 6 35 2 Remove and discard two stepjoint sealrings from the hub of the front support fig 6 35 Remove the needle roller bearing assembly if not previously removed and bearing race NOTE Check the bolt size and location of the nine bolts removed from t h e inner circle of the front support Some models use six b o 1 t s of one length and three bolts of another length 3 Remove the nine bolts from the inner circle and sixteen bolts from the outer circle fig 6 35 Carefully separate the front support and valve assembly from the retarder housing io 6 36 Remove retarder housing gasket 4 Position front support and valve assembly fig 6 36 front mounting side downward b Refer paragraph 6 10a 6 7 8 9 and 11 for disassembly of the support assembly FRONT SUPPORT ASSEMBLY RETARDER HOUSING GASKETS BOLT 388 15 X 2 1 4 i0 BOLT 38 16 X 1 14 116 1 54 52 Fig 6 35 Retarder housing and front support assembly FRONT SUPPORT AND RETARDER HOUSING VALVE ASSEMBLY 24 RETARDER HOUSING GASKET 3751 Fig 6 36 Removing or installing front support and valve assembly from retarder housing 6 Remove plugs 20 foldout 12 from the bottom of the retarder housing Copyright 1983 General Motors Corp 6 27 HT 740D HT 750
295. ive wear cone distortion imbedded metal galling cracks breaks and damaged tangs Remove burs and minor surface irregularities using a soft honing stone Replace plates which have other defects 3 The amount of cone in clutch plates is determined by measuring the distance between the inside diameter of the plate and a level surface 8 Discard plates having excessive cone refer to wear limits When assembling a clutch pack soak friction faced clutch plates in transmission fluid for at least 2 minutes and make sure that each plate is installed so that its cone is in the same direction as the cone of the adjacent plates Inspecting Swaged Interference fit Parts If there is evidence of looseness the assembly should be replaced p Inspecting Balls in Clutch Housings Inspect all balls in rotating clutch housings for free movement Any restriction could prevent the ball from seating during clutch application Inspect staking that retains the balls LEVEL SURFACE CLUTCH PLATE MEASURE HERE FOR CONE 5067A Fig 4 8 Method of measuring clutch plate cone Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS Inspecting Sealing Surfaces 1 At locations contacted by hooktype and step joint sealrings inspect the i n s i d e diameter for step wear nicks scratches and scoring Remove only the raised metal portion of these defects with a soft stone or crocus cloth Polishing
296. iven PTO units is 0 018 to 0 024 inch S Fi ru S NT i WT ed d Li rie te xx iy be e A E i ub i E j mg SA y a n3 tal ai Whi y are to qu io m ind po d eg xi 1 d Pg 2e i ge ae eT a Reel el VU S 3 a 4 AS 4 TEB x 5 E hs doen i Ye a T lj es x i RE cm aed s A eU de Boj Dom eie SUL Fig 7 65 Installing converter housing retainer bolt 0 457 to 0 610 mm prior to S N 32403 and 0 006 to 0 012 inch 0 15 to 0 30 mm after S N 32403 CAUTION Cork or other soft gasket material cannot be used to mount the PTO Use only the shims or gaskets recommended by the PTO manufacturer 4 Install two headless gude bolts one into the top and one into the bottom of the PTO mounting pad Place the required shims or gasket on the guide bolts CAUTION The transmission and PTO can be damaged if the PTO is installed with its driven gear to the front of the PTO drive gear 5 If the PTO has a manual disconnect be sure that the disconnect lever is in the disconnect position When the PTO is installed on the mounting pad the PTO driven gear must be to the rear of the PTO drive gear in the transmission 6 Install the PTO on the mounting pad Copyright 1983 General Motors Corp ASSEMBLY OF TRANSMISSION 7 Connect the lubrication line if used
297. iving hub Friction face thickness Forward clutch running clearance refer to para 6 17 FOURTH CLUTCH ASSEMBLY Clutch backplate thickness Internal splined clutch plate thickness External tanged clutch plate Thickness Cone Fourth clutch running clearance refer to para 6 18 Wear Limit in mm 0 007 0 18 0 007 0 18 0 0993 2 522 0 010 0 25 0 090 2 29 0 390 9 91 0 390 9 91 0 090 2 29 0 0993 2 522 0 010 0 25 THIRD CLUTCH CENTER SUPPORT SECOND CLUTCH Third clutch backplate thickness Internal splined clutch plate thickness Internal splined clutch plate thickness Internal splined clutch plate thickness External tanged clutch plate Thickness Cone External tanged clutch plate Thickness Cone Center support bushing clearance on sun gear shaft 25 B foldout 15 or 25 A Minimum depth of oil grooves 0 008 inch 0 20 mm Copyright 1983 General Motors Corp 8 3 0 490 12 45 0 1347 3 421 0 1347 3 421 0 1347 3 421 0 0993 2 522 0 013 0 33 0 1161 2 949 0 013 0 33 0 0065 0 165 Illustration B foldout 14 A foldout 15 2 4 7 13 24 26 25 27 B foldout 15 and A foldout 16 2 4 7 13 24 26 25 27 B foldout 16 8 foldout 18 1 Part Number 6881352 6881638 6835322 6835321 6835323 6883702 6835322 6883492 6881352 6881638 6835322 6835321 6835323 6883702 6835322 6883492 6881746 6834680 6834766 HT 740
298. ker step will not The prescribed clearance is 0 080 to 0 120 inch 2 03 to 3 05 mm Any clearance measurement within this range is satisfactory but the nearer to 0 080 inch that can be attained the longer the clutch will maintain satisfactory clearance 14 If the clutch clearance is not within the specified limits remove snapring Copyright 1983 General Motors Corp 6 31 HT 740D HT 750D SERIES TRANSMISSIONS 1 24215 U1 ei 1 Wwe pe on ee Le CT um i Dorr UE a IIR NUN a PS iW MR LA E usi Pri fe a Ree ed i am Is cd EAS y Re ELE zu M Lo Lear Fa 1 i 2 PAS i 1 aes dem 1 F ES Ir 2 Fig 6 44 Installing forward clutch piston F fourth clutch driving hub D and clutch plates B and C Replace clutch plates as required to obtain the desired clearance Refer to wear limits in Section 8 to determine the plate thicknesses 15 Repeat i t e m s 12 and 13 above When the clutch clearance is within the specified limits of 0 080 to 0 120 2 03 to 3 05 mm remove snapring F and hub D clutch plates B and C and piston A 16 Place piston A on a work table with the return spring bosses up Grease and install two new lip type teflon sealrings into the inner and outer sealring grooves in the piston 17 Install sealring protector J 24216 01 onto the clutch housing hub fig 6 44 18 Lubricate the piston sealrings with transmission fluid a
299. ks 1000 hours At 200 000 miles After first 600 off highway or 12 months 321 800 km hours thereafter or overhaul 1200 hours max Whichever occurs first Oil may require change sooner depending on operating conditions Oil must be changed whenever there is evidence of dirt or high temperature condition indicated by discoloration strong odor or oil analysis Local conditions severity of operation or duty cycle may dictate more or less frequent service intervals d Oil and Oil Filter Change Procedure 1 The oil should be warm when draining This will ensure quicker and better drainage 2 On earlier models remove the fill tube from the oil pan and allow the oil to drain On later models remove the drain plug from the rear of the oil pan and allow the oil to drain Check the condition of the oil as described in NOTE Procedures outlined in 3 through 10 are required only when the suction screen in the oil pan must be replaced refer to oil and filter change intervals chart 3 After draining is completed remove twenty three washer head screws 42 B foldout 16 that retain the oil pan to the transmission housing Discard pan gasket 38 and clean the pan with mineral spirits or paint thinner 4 Remove washer head screw 30 foldout 16 and washer 31 Remove oil filter 33 and spacer 32 on later models Inspect the filter If damage has occurred replace the filter If the filter is in satisfactory co
300. l Non retarder model Rear governor pressure Oil temperature Normal operating Lockup operation Converter operation Retarder operation Transfer gear housing Parking brake provision Drive range and sequences HT 740D HT 750CRD HT 754CRD HT 750DRD HT 750DRD DB Drive range and shift control Shifting mechanism Shift modulation upshift and downshift Neutral start and reverse signal switches Speedometer drive Type Drive gear data Driven gear 30 psi 1900 rpm 25 psi 1900 rpm Refer to table at end of section 1 Converter Out To Cooler Sump 160 200 F 71 93 C 150 66 C min 250 F 121 C max 250 F 121 C max 300 F 149 C max 250 F 121 C max A 330 F 165 C max 250 F 121 C max a 250 F 121 C max 12 x 5 304 8 x 127 0 mm customer supplied 50 Ib 22 68 kg Reverse neutral 1 Reverse neutral 1 1 2 3 1 2 1 2 3 4 2 3 4 a Heverse neutral 1 2 3 4 5 1 2 3 4 1 2 3 1 2 1 Heverse neutral 2 3 4 5 2 3 4 2 3 2 1 Heverse neutral 2 3 4 5 2 3 4 2 3 2 1 Mechanical external Hydraulic internal control Mechanically actuated cable cam modulator valve Supplied by customer Spiral gear 6 tooth rh helix angle Supplied by customer Copyright 1983 General Motors Corp 1 11 HT 740D HT 750D AUTOMATIC TRANSMISSIONS SPECIFICATIONS AND DATA CHART cont B9
301. lanetary carrier 19 Bronze thrust washer 8 20 Pinion 4 21 Needle roller bearing 8 22 Steel thrust washer 8 23 Sun gear and shaft assembly 24 Split sleeve bushing 25 Center sun gear shaft 26 Split sleeve bushing 2 Thrust washer 28 Planetary connecting drum 29 External snapping 30 Center planetary ring gear 31 Thrust race 32 Needle roller bearing 33 Thrust race 34 Main shaft assembly 35 Orifice plug 36 Main shaft 3 Rear planetary sun gear 38 External snapping 39 Rear planetary carrier assembly 40 Rear planetary carrier 41 Pinion pin 42 Bronze thrust washer 8 43 Needle roller bearing 4 44 Pinion 4 45 Steel thrust washer 8 46 Internal snapping 1 Transmission breather 1A Transmission breather reducer 2 Lockwasher 1 2 11 Non retarder 3 Bolt 1 2 13 x 2 11 Non retarder A 4 Pipe plug 1 8 B 5 Drive screw 6 Nameplate 7 Transmission housing assembly 8 Transmission housing 9 Pipe plug 1 4B 10 Plain washer 3 8 11 Bolt 3 8 16 x 3C 12 Oil baffle 13 Bolt 1 4 20 x 1 1 2 2 D 14 Plain washer 1 8 15 Bolt 1 4 20 x 1 1 2 D 16 Bolt 1 4 20 x 1 1 2 7 D 17 Plain washer 1 4 18 Bolt 1 4 20 x 1 1 2 D 19 Bolt 1 4 20 x 3 1 2 0 D 20 Bolt 1 4 20 x 3 15 D 21 Bolt 1 4 20 x 2 1 2 D 22 Detent roller and spring assembly 23 Cover plate 24 Bolt 1 4 20 x 2 8 D 25 Signal
302. lid blue orange stripe oolid blue white stripe Solid yellow blue stripe oolid orange white stripe oolid orange yellow stripe Solid blue Solid white yellow stripe oolid orange Solid white Solid red oolid blue yellow stripe Table 8 2 SPRING DATA cont Spring Free No Wire dia OD Length Length Under Load Coils 1n mm 1n mm 1n mm 1n mm 16 N 10 0 099 0 940 2 18 1 94 6 2 to 7 4 2 51 23 9 55 4 49 3 27 6 to 32 9 8 5 0 092 0 690 1 45 1 10 21 70 to 25 30 2 32 17 5 36 8 27 9 96 5 to 112 5 9 0 098 0 949 2 27 1 94 9 4 to 11 4 2 49 24 1 57 7 49 3 41 8 to 50 7 20 0 062 0 564 2 77 1 49 11 6 to 12 8 1 57 14 3 70 4 37 9 51 6 to 56 9 8 5 0 092 0 690 1 45 1 10 21 7 to 25 3 2 33 17 5 36 8 27 9 96 6 to 112 6 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 2 33 17 5 42 9 27 9 145 0 to 177 0 9 6 0 092 0 690 1 69 1 10 32 6 to 39 8 2 33 17 5 42 9 27 9 145 0 to 177 0 8 7 0 121 0 950 2 38 1 94 29 0 to 35 0 3 07 24 1 60 5 49 3 129 0 to 155 7 7 4 0 092 0 930 2 27 1 94 9 4 to 11 4 2 33 23 6 57 7 49 3 41 8 to 50 7 10 0 103 0 940 2 56 1 94 20 to 22 2 61 23 9 65 0 49 3 89 0 to 97 9 10 0 099 0 940 2 18 1 94 6 2 to 7 4 2 51 23 9 55 4 49 3 27 6 to 32 9 9 0 098 0 949 2 27 1 94 9 4 to 11 4 2 49 24 1 57 7 49 3 41 8 to 50 7 11 0 073 0 690 2 18 1 20 16 2 to 19 8 1 85 17 5 55 4 30 5 72 1 to 88 1 11 0 073 0 680 1 52 1
303. lied first clutch and the rear sun gear rotating the pinions the rear planetary carrier must rotate within the ring gear and drive the output shaft at a speed reduction of 3 69 1 Copyright 1983 General Motors Corp 2 25 HT 740D HT 750D AUTOMATIC TRANSMISSIONS TORQUE FORWARD LOCKUP HIR LUCH THIRD CLUTCH CONVERTER CLUTCH powb E Pra fie i SHAFT S y FOURTH LE i teu CLUTCH i 3 SHAFT SUN GEAR SHAFT 4 RI IM per Xu T 4 1 i T od mm PIE E pronis Heinr p n d TES ls Auk pus eui E Ts 1 ame i a 15 i PUR XD ice qe a E i gy m a BEES pe Sao pero i F J CONNECTING DRUM FRONT PLAN ETARY CENTER PLANETARY SECOND EE CLUTCH Fa o FIRST CLUTCH 7 OUTPUT SHAFT REA K SUN GEAR Fig 2 4 Second gear torque path HT 740D HT 747D e Second Gear Operation f ig 2 4 Engine torque is transmitted through the torque converter as described in a above The forward and the second clutches are applied The second clutch application anchors the carrier of the front planetary assembly against rotation The forward clutch application locks the input shaft and main shaft together so that they rotate as a unit The rear sun gear is splined to both the rotating main shaft and the center ring gear and all three parts rotate at input speed With the c
304. ll Seal 1 Before installing the lip type seal refer to paragraph 4 6 f for seal preparation Install oil seal 18 or 50 foldout 23 or 6 B foldout 23 spring loaded lip first Use installer J 24202 1 and driver handle J 24202 4 to seat the seal against the shoulder in the housing 2 3 Install retainer 21 or 53 foldout 23 or B foldout 23 and two bolts 23 or 55 A foldout 23 1 B foldout 23 Install the output flange onto the shaft Copyright 1983 General Motors Corp 3 16 PREVENTIVE MAINTENANCE Tighten the bolts sufficiently to ensure the flange is firmly seated on the shaft then remove the two bolts and retainer 4 Measure the distance from the counterbored surface of the output flange to the end of the output shaft Select a combination of shims 19 and 20 or 51 and 52 foldout 23 or 4 and 5 B foldout 23 that will be 0 008 to 0 012 inch 0 20 to 0 30 mm less than the measured dimension 5 Install the selected shims retainer lockstrip 22 or 54 A foldout 23 or 2 B foldout 23 and two bolts for each flange Tighten the bolts to 96 115 Ib ft 130 156 N m Bend a corner of the lockstrip against each bolt head 6 Connect the equipment drive shaft to the output flange 3 17 CHECKING OIL PRESSURES Oil pressures m a y be checked during operation of the transmission to assist in the location of malfunctions Pressure check points are shown in figures 3 6 3 9
305. llation Copyright 1983 General Motors Corp 4 14 GENERAL OVERHAUL INFORMATION 3 Nonhardening sealing compound The circumference of some seals is not precoated with a dry sealant A nonhardening sealant should be applied to the circumference of these seals before installation g Butt joint Sealrings 1 Butt joint sealrings require special handling during assembly sealrings contain materials which will absorb moisture from the atmosphere and expand the sealring The sealrings are sealed in air tight packages and should not be opened until you are ready to install them into the transmission Before installing the sealring the end clearance must be checked to ensure that the sealring has not been expanded CAUTION If humidity is allowed to penetrate and expand the butt joint sealring the sealring can be damaged during installation A damaged sealring will leak oil from the clutch piston cavity and cause clutch slippage Do not open the sealed package until you are ready to install the sealring 2 Remove the sealring from its sealed package Place it in its operational position inside the bore that it will be sealing 3 Using a feeler gage check the end clearance of the sealring The end clearance must not be less than 0 010 in 0 25 mm 4 Ifthe end clearance is less than 0 10 in 0 25 mm bake the sealring in an oven at 200 3000F 93 1490C for 24 hours or get a new sealring Repeat steps 2 an
306. location regardless of model or clutch drive function will have the same name 2 These names will parallel the names assigned to clutches in the first edition of the manual except for the added clutch in five speed models Refer ae Saher uniform clutch designations c Planetary Gear Set Designations 1 Each gear set in the same physical location regardless of model or gear drive function will have the same name 2 These names will parallel the names assigned to gear sets in the first edition of the manual except for the added gear set in five speed models Refer uniform gear set Ld FORWARD ed iom THIRD i udo CLUTCH 4025 02 FRONT GEAR SET FOURTH uae d CENTER GEAR SET EE m CLUTCH 2 11 FORWARD CLUTCH AND TURBINE SHAFT B foldout 13 Function Differs Among Models 1 The forward clutch in the HT 740D HT 747D has a multiple function When engaged simultaneously with the first clutch it produces first gear When engaged with second clutch third or fourth clutches it produces second third or fourth gears in that sequence 2 In the HT 750CRD HT 754CRD and HT 50DRD the forward clutch has multiple functions When engaged with low clutch it produces first gear When iibi a SECOND FIRST ur LOW CLUTCH T CLUTCH PeR models ong WW LOW GEAR SET 5 SPEED MODELS ONLY 52996 Fig 2 1 Uniform clutch and gear designation for 7000 series tran
307. lutch When D1 position was selected main pressure was directed from the selector valve to the forward clutch With the application of two clutches torque can be transmitted to the output shaft 7 When t h e circuits are charged for drive 5 D5 as described above any forward shift from second to third third to fourth and fourth to fifth can occur automatically These shifts occur as a result of rear governor pressure At less than full throttle modulator pressure will assist governor pressure 8 Position of the selector valve determines the highest gear which will be normally reached automatically In drive 5 D5 automatic 2 3 3 4 4 5 shifts can occur In drive 4 D4 automatic 2 3 3 4 shifts can occur In drive 3 D3 automatic 2 3 shift can occur In drive 2 D2 no upshift will occur remains in second gear In drive 1 D1 no upshift will occur remains in first gear Automatic downshifts can occur within any selected range except D1 or D2 9 Refer to paragraph o 8 9 above for operation of hold regulator valve q A Automatic Upshifts 1 When the transmission is operating in D4 HT 740 HT 747D or D5 HT 750 a combination of rear governor pressure and modulator pressure or rear governor pressure alone will upshift the transmission to the next gear At closed or part throttle modulator pressure exists and will assist rear governor pressure At full throttle there is no modulator pressure Thus
308. lywheel bolts HOIST GUIDE BOLT J 24315 2 p IB BI LIFTING TOOL 3 e FLYWHEEL ASSEMBLY A CONVERTER PUMP Fig 5 7 Lifting tool installed on flywheel 4 Attach a hoist to the lifting tool Support the weight of the flywheel during removal of the remaining bolt and washer 5 Remove the flywheel and attached parts f r o m the converter housing fig 5 8 Copyright 1983 General Motors Corp 5 4 m y CONVERTER HOUSING DISASSEMBLY OF TRANSMISSION 53776 Fig 5 8 Removing flywheel and turbine NOTE Whether the turbine is removed with the flywheel as shown or remains on the transmission use care to prevent its falling 6 Remove the turbine from the flywheel or transmission Refer to paragraph 6 rebuild of the turbine and flywheel assembly 5 6 REMOVING OIL PAN FILTER VALVE BODY HT 740D 747D a Oil Pan Filter 1 Rotate the transmission to a vertical position front end converter housing upward Remove two oil pan screws fig 5 9 and install two 5 16 18 g u i d e bolts J 3387 2 Remove the remaining twenty one pan screws Remove the oil pan and gasket Remove the guide bolts 518 23 0 Fig 5 9 n bb Removing oil pan screws ER a TDI n cn 51926 Fig 5 10 Removing oil filter screw 7400 7470 4 Remove the screw that retains the oil filter fig 5 10 Remove th
309. management member of the distributorship with whom the dealer has his service agreement otep Two When it appears that your problem cannot readily be resolved at the distributor level without additional assistance contact the Detroit Diesel Allison Hegional Office nearest you listed below EASTERN REGION ouite 202 10 Parsonage Road Edison New Jersey 08837 USA Phone 201 246 5070 TW X 710 998 0563 SOUTHEASTERN REGION 5 30 Glenridge Drive NE Atlanta Georgia 30328 USA Phone 404 257 3640 TWX 810 751 8141 GREAT LAKES REGION Room 104 Garrison Place 19855 West Outer Drive Dearborn Michigan 48124 2098 USA Phone 313 565 041 1 TWX 810 221 6283 MIDWESTERN REGION 475 Alexis R Shuman Blvd Naperville Illinois 60566 USA Phone 312 961 6750 TWX 910 651 3032 SOUTHWESTERN REGION General Motors Building 130 E Carpenter Freeway Irving Texas 75062 USA Phone 214 659 5070 TWX 910 860 5063 WESTERN REGION Suite 2700 39465 Paseo Padre Parkway Fremont California 94538 USA Phone 415 498 5200 TWX 910 381 6105 Copyright 1983 General Motors Corp CANADA Diesel Division GM of Canada Ltd P O Box 5990 600 Clarke Road London Ontario N6A 4L6 Canada Phone 519 452 5000 Telex 064 5850 TWX 610 352 0269 LATIN AMERICAN REGION Detroit Diesel Allison Gables Center suite 321 95 Merrick Way Coral Gables Florida 33144 USA Phone 305 446 4900 Telex 810 848 7061 EUROPEAN
310. mbly 3 Remove sun gear and shaft assembly 6 and thrust washer 7 If the bushings in gear and shaft assembly 6 are worn or damaged remove them 4 Remove snapring 8 and ring gear 9 from the front of planetary connecting drum 17 5 Lift out center planetary carrier assembly 10 Refer to paraaraph 6 23 rebuild of the carrier assembly Remove snapring 23 Remove low sun 6 gear 24 7 Remove bearing race 20 bearing 21 and bearing race 22 8 Remove main shaft 11 Remove center planetary ring gear 12 and its attached parts items 13 14 15 16 19 9 Remove snapring 13 Lift ring gear 12 from sun gear 16 Remove race 14 bearing 15 and race 19 10 Remove snapring 18 and lift rear planetary carrier assembly 25 from drum 17 Refer to for rebuild of carrier assembly Copyright 1983 General Motors Corp 6 45 HT 740D HT 750D AUTOMATIC TRANSMISSIONS NOTE Refer to above b Assembly Bj foldout 15 1 If the bushings w e r e removed from sun gear and shaft assembly 6 fig 6 66 refer to paragraph 2 If orifice plug 35 B foldout 15 was removed from shaft 36 install a new plug Refer to oaragraph 6 20c l above for replacement 3 Position planetary connecting drum 17 fig 6 60 front longer internal splines downward Install rear planetary carrier assembly 25 larger carrier bore first into drum 17 Retain the carrier with snapring 18 4 Install bea
311. me is determined by the size of the bearing Forty five minutes is sufficient for the largest bearing in these transmissions 2 bearing must be removed or installed without a sleeve be careful to drive or press only on the race which is adjacent to the mounting surface If a press is not available seat the bearing with a drift and a hammer driving against the supported race Copyright 1983 General Motors Corp 4 15 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 4 7 REMOVING OR INSTALLING TRANSMISSION a Drain Oil D rai n the oil from the transmission before removal from the vehicle 3 7 For better drainage the transmission should be warm and allowed to drain over night Since applications will differ consult the vehicle service manual for specific instructions for transmission removal and installation b Check Linkages and Lines Make sure that all linkages controls cooler lines modulator actuator cable temperature connection input and output couplings and mounting bolts are disconnected before transmission removal also oil filler tube and other equipment such as attached parking brake handle etc Oil lines should be carefully placed out of the way of damage and all openings covered to keep out dirt NOTE Position jack or hoist sling to coincide with the transmission center of gravity as follows measured rearward from front mounting of transmission to engine HT 740D 13 50 in 343 mm HT 7
312. mendations of the bearing manufacturer and therefore no diametral dimensional deviation should be permitted in the bearing or mated parts Bearings should be carefully checked for signs of distress before reinstalling in the transmission d Gears Gears should be inspected for load pattern and signs of distress Any distress indicates a possible future failure and the reuse of such gears should be the decision of the individual customer based on experience Backlash cannot be used to establish critical we ar of agear The backlash tolerances are of such nature that a gear usually pits scuffs scores or galls long before the gear wear becomes critical e Splines Unless severe spline wear is not considered detrimental except where it affects tightness of an assembly such as driveline flanges Backlash cannot be used to establish critical wear because both mating parts must be concentrically located to obtain accurate measurement of backlash f Hook type Sealrings Sides of the sealring should be smooth w i t h maximum wear of 0 005 inch 0 13 mm The sides of the groove into which the sealrings fit should be smooth within 50 microinch 1 27 micrometers and square with the axis of rotation within 0 002 inch 0 05 mm new sealring should be installed if grooves are reworked or if there is wear on the sealring outside diameter g Oil Seals Seals should be replaced if they s h O W Signs of excessive hardening scoring cracki
313. missions equipped with a power takeoff at the top and or side of the converter housing complete the installation as outlined in paragraph 7 12b 9 through 13 7 15 INSTALLING TORQUE CONVERTER PUMP STATOR ASSEMBLIES a Pump Assembly 1 Install the torque converter pump assembly as rebuilt in paragraph 6 5 onto 54 ftd Fig 7 45 Installing converter housing bolts retarder models Copyright 1983 General Motors Corp 7 25 Fig 7 46 Installing torque converter pump assembly the ground sleeve fig 7 46 Check the sealring on the hub NOTE After transmission S N 2081 the pump bearing is a press fit on the ground sleeve It may be necessary to heat the hub and bearing area of the pump assembly to 300 F 149 C HT 740D HT 750D AUTOMATIC TRANSMISSIONS SAFETY GUARD HANDLES Fig 7 47 Converter pump snapring tool With oil before installation zi ay 2d E Align the slots in the pump hub with 2i mee tangs in the oil pump drive gear as the pump is being 1 installed fig 7 46 E Pd ti Install spacer 27 foldout 10 onto Loy f Ti TEA the converter ground sleeve 4 Place snapring 26 into tool J 26598 as follows Close the jaws of the tool by rotating the adjusting nut fig 7 47 Place the snapring in the tool under the safety guards Position the jaws of the tool in the snapring gap Open the jaws of the tool by rotating the adjusting nut to the stop nut 5 Place the
314. mm P SEAL jal an GASKET Fig 6 101 Removing or installing bearing retainer bolts 2 Remove the disconnect output shaft and bearing EAA Remove the two detent balls and their spring which will be freed when the shaft Is removed 3 Remove the shifter shaft by rotating it counterclockwise fig 6 102 4 Do not remove the ball bearing assembly or the needle bearing race from the disconnect output shaft unless replacement is necessary Copyright 1983 General Motors Corp REBUILD OF SUBASSEMBLIES OUTPUT SHAFT Fig 6 102 Removing output disconnect shaft b Remove the output driven coupling 6 103 Remove the shifter fork 6 Do not remove the shifter shaft oil seal from the housing unless replacement is necessary 6 103 NOTE Refer to paragraph 6 2 b Assembly A 1 If the shifter shaft oil seal was removed from the body fig 6 103 install a new oil seal Press the seal spring loaded lip first into the body until it seats lightly against the shoulder in the body bore 2 Install the shifter fork long side of threaded boss away from the oil seal into the body 6 104 3 Install the output driven coupling into the body and engage the shifter fork with the external groove in the coupling fig 6 103 4 If the ball bearing assembly was removed from the disconnect output shaft Fig 6 103 Removing or installing disconnect driven coupling BODY
315. move nine bolts and washers retaining the converter housing to the transmission housing Two bolts were removed before the installation of the lifting bracket Refer to figure 5 1 Remove t h e converter housing from the transmission housing with the lifting sling and place it on the work table fig 5 30 Refer to paragraph 6 10 for rebuild of the converter housing assembly Remove the pitot tube or steel block fig 6 5 30 freed in item 1 Copyright 1983 General Motors Corp 5 12 Fig 5 29 Fig 5 30 DISASSEMBLY OF TRANSMISSION n FE WIS se SF soir 12 13211 4 WASHER V2 7 E P SCREW 10 32 x 2 2 8 WASHER M0 2 dte Uc UNE Tu qe 51934 Removing pitot tube or block screws nu Sh J 51335 Removing torque converter housing b Housing with 2 Bolt Top Cover with retarder 1 From inside the converter housing remove the seven bolts fig 5 31 2 Remove seven bolts 63 and washers 62 CIE TR retaining the converter and retarder housings to t h e transmission housing one bolt removed when holding fixture Remove three nuts 56 and three washers 57 3 Separate t h e converter housing from the retarder housing being careful that the retarder housing is not lifted from the transmission housing fig 5 32 If the retarder housing is lifted the pitot tube and or oil collector ring can be damaged When free remove the converter housing Refer to
316. move the adapter housing and gasket from the transmission housing Refer mE 7 27 5 Remove the thirteen first clutch plates from the transmission housing These plates were preset for proper clearance and should be maintained as a package for final installation 6 Using gage J 24194 check the second clutch plate clearance fig 7 7 It is recommended the gage be placed between the transmission housing and the first steel plate The prescribed clearance is 0 095 to 0 145 inch 2 41 to 3 68 mm Any dimension within 0 095 to 0 145 inch is satisfactory However the closer the clearance is to 0 095 inch the longer the interval between clutch plate replacements will be Replace worn plates with new plates to establish the desired clearance Recheck the clearance as described above NOTE Leave the second clutch and the center support in the transmission housing until the housing is again positioned front end upward Begin assembly of Model HT 750CRD HT 754CRD at Begin assembly of Model HT 750DRD at 7 5 INSTALLING REAR COMPONENTS HT 740D 747D a First Clutch 1 Place the transmission housing in a vertical position rear upward 2 Install the first clutch pack removed in 7 3c 3 or first clutch components selected by stack method 3 Beginning with an external tanged clutch plate install five external tanged and five internal splined clutch plates fig 7 12 4 Install the rear planetary ring gear longe
317. must be disassembled and closely inspected to find the source Metal contamination will require complete disassembly of the transmission and cleaning of all internal and external circuits cooler and all other areas where the particles could lodge c Coolant Leakage 1 The presence of ethylene glycol coolant in the transmission oil is detrimental to the reliability and durability of the internal components Ethylene glycol has a deteriorating effect on non metallic components seals gaskets etc and on highly loaded steel parts such as bearings and gears due to reduced lubricity of the oil 2 Should the presence of ethylene glycol in the oil be suspected an immediate verification test should be made A GlyTek Testkit is available and is a quick and easy method to determine the presence of glycol If glycol is found disassemble the transmission inspect and remove all traces of coolant and varnish deposits resulting from coolant contamination Replace seals gaskets and friction clutch plates Copyright 1983 General Motors Corp 3 6 PREVENTIVE MAINTENANCE d Auxiliary Filter models without hydraulic retarder After a transmission failure occurs that introduces debris into the oil system a complete cleanup of the oil system is required Repeated cleaning and flushing will not ensure a clean free from debris oil system due to cooler retension To prevent a repeated transmission failure installation of an auxiliary
318. n the disconnect housing to the transfer gear housing for each of the disconnect assemblies d Installing Output Input Flanges 1 Install output flanges as required The nuts that retain the flanges and the threads on the output shaft should be lubricated before installing the nut LE penuti sw nut to 600 9 800 Ib ft 813 to 1085 Nem Refer to paragraph 3 14 2 Install flanges onto the manual disconnect output shafts Install retainer 3 foldout 23 Or retainer 22 or 55 foldout 23 Install the retainer bolts and tighten Mp sufficiently to ensure that the flange is firmly seated och 2 thru 5 3 Remove the bolts and retainer Select a combination of 20 21 53 and 54 A foldout 23 that will be 0 008 to 0 012 inch 0 20 to 0 30 mm less than the space between the flange retainer against the counterbore in flange and the end of the output shaft 4 Install the shims retainer lockstrip and two bolts Tighten the bolts to 96 to 115 Ib ft 130 to 156 Nem Bend a corner of the lockstrip against each bolt head e Bearing Retainer amp Cover 1 If cover 3 B foldout 22 was used on the lower front position of the dropbox install gasket 4 and cover 3 Retain the cover with eight 1 2 13 x 1 1 4 inch bolts and eight lockwashers Tighten the bolt to 67 to 80 Ib ft 91 to 108 Nem Copyright 1983 General Motors Corp 7 35 HT 740D HT 750D AUTOMATIC TR
319. n the holes in the retainer converter pump and pump hub Install one 3 8 24 X 1 1 4 inch bolt 27 and one lockstrip 28 at the 12 o clock position Do not tighten the bolt 6 Install three more bolts and lockstrips one each at 3 6 and 9 o clock positions Snug the bolts in the 12 6 3 and 9 o clock sequence 7 Tighten the four bolts in the same sequential manner 33 40 Ib ft 44 54 Nem 8 Install the retaining eight bolts and lockstrips Tighten the bolts 33 40 Ib ft 44 54 N m and bend the corner of each lockstrip to retain the twelve bolts Install gasket 40 onto hub 42 9 Retain the ground sleeve in a rigid position Install the assembled converter pump onto the ground sleeve until the bearing is properly seated 10 Rock the pump about the bearing noting outer pump lip travel Total rock must be at least 0 015 inch or bearing must be replaced NOTE Failing to use t h e sequential torque procedure for installing the twelve retainer bolts and the recommended rocking clearance check will lead to premature bearing failure 11 If bearing 37 was removed replace it with new split race bearing 36 Discard gasket 41 Refer to paragraph b 2 through 10 12 If bearing 38 was removed install a new bearing grooved end last into drive gear 39 13 Install drive gear 39 and bearing 38 on to converter pump 33 Retain drive gear 39 and bearing 38 to converter pump 33 with retainers 29 twelve bolts 27 and si
320. nd valve body for correct retainer installation Compress spring 67 and install retainer pin 69 27 Install governor screen assembly 64 open end first into bore Q Retain the screen assembly with plug 65 Tighten to 5161 in Ib 5 6 6 8 N m 28 Install check valve pin 6 smaller end first through the top side of oil transfer plate 7 Install lubrication valve 2 spring 3 and cup washer 4 onto pin 6 from bottom side of plate 7 Depress cup washer 4 and install retainer pin 5 29 Position oil transfer channeled side upward on the work table plate 7 30 Place each check valve ball into the oil transfer plate in the same position it was removed during disassembly Retain the balls in the plate with oil soluble grease If correct ball location is not known refer to the transmission assembly number in the control valve section in Parts Catalog SA 1268 Copyright 1983 General Motors Corp 6 14 REBUILD OF SUBASSEMBLIES NOTE Failure to retain the balls with oil soluble grease may result in balls being accidentally misplaced during subsequent assembly steps 31 Place separator plate 29 B foldout 20 onto the oil transfer plate so that their bolt holes align Grasp the two plates together invert them and position them on the assembled control valve body so that priority valve 73 is compressed against spring 72 into its bore in valve body 30 NOTE Do not separate the oil transfer Plate and the se
321. nd centrally locate the piston in the housing bore Place the piston and piston housing under an arbor press and apply pressure evenly until the piston is properly seated 19 If a press is not available seat the piston in the housing bore by tapping the piston lightly with a mallet in a continuous alternatel foldout 13 33748 Fig 6 45 Checking forward clutch plate running clearance circular pattern until the piston is properly seated Install twenty piston return springs 13 B 20 foldout 13 onto the spring guide bosses of piston 12 Place spring retainer 14 on top of the twenty springs recessed side outer lip of the retainer facing down 21 Compress spring retainer 14 B foldout 13 until the snapring groove on the clutch housing hub is exposed Install the snapring into the groove 22 15 above Install the clutch plate pack removed in Beginning with an external tanged plate install five external tanged plates 20 B and five internal splined plates 21 into the forward clutch housing 23 Grease with oil soluble grease and install the thrust bearing race onto the inner hub of forward clutch housing fig 6371 24 Grease with oil soluble grease and install the bearing race and needle bearing onto the inner hub of the forward clutch hub Copyright 1983 General Motors Corp 6 32 REBUILD OF SUBASSEMBLIES 25 Install the forward clutch hub outer splines first into the forward clutc
322. ndition clean and reuse it Remove clean and reinstall the governor feed line screen in the valve fig 5 13 Refer to b Prior to installing filter 33 install new sealring 34 B foldout 16 onto the oil intake pipe integral with filter Lubricate the sealring with transmission fluid Copyright 1983 General Motors Corp 3 5 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 6 Install the oil filter aligned so that filter does not require twisting inserting the oil intake pipe into the hole in the bottom of the transmission Secure the oil filter with a 5 16 18 x 1 5 8 inch washerhead screw Tighten the screw to 10 13 Ib ft 14 18 N m 7 Place the oil pan gasket onto the oil pan A sealer or cement may be applied only to the oil pan flange area that is outside the raised bead of the flange Do not use grease on cork gaskets CAUTION Gasket cements sealing compounds vegetable based cooking compounds or fibrous nonsoluble greases should never be used inside the transmission Only oil soluble grease petrolatum should be used for retaining parts except cork gaskets temporarily 8 Install the oil pan and gasket carefully guiding them into place Guard against dirt or foreign material entering the pan Retain the pan to the housing with four 5 16 18 X 5 8 inch washer head screws Install a screw into each corner of the pan 9 Install the remaining nineteen washer head screws carefully threading each one th
323. ne the bushings as shown in LI CMS Chuck speed should be 300 to 400 rpm and REFET En feed should be approximately 0 006 in 0 15 mm iquam sur 34215 Fig 6 59 Sun gear shaft and swaging tool Copyright 1983 General Motors Corp 6 40 REBUILD OF SUBASSEMBLIES Ae E PILOT TOOL ms B J 28489 1 a nem S EAMER AND FE SHAFTASSY J 28489 2 1 i SUN GEAR SHAFT ASSY i i pus i m n 1 hl ied Eon HT M HOLDING Sr FIXTURE C ECT a J E 3 D EST 3 diss Fig 6 60 Sun gear shaft assembly and tools for reaming rear bushing NOTE If sun gear bushing reamer set J 28489 is not available perform step 6 lf tool J 28489 is available proceed with step 7 7 If tool J 28489 is available assemble the parts shown in figure 6 60 in the following manner Clamp the holding fixture in a vise fia 6 611 Place the sun gear shaft assembly in the holding fixture and put the reamer and pilot tool in place Using a 1 2inch 30 5 mm electric drill machine the bushing approx 7 5 to 150 rpm while adding cutting lubricant through the hole s in the pilot tool CAUTION Keep reamer at full drill speed when pulling it back through the bushing If reamer is not _ CUTTING LUBRICANT Fr BENE SUN GEAR cu de SHAFT ASSY ae ame m aN HOLDING w PEEL PILOT TOOL FIXTURE SML UM 1 28489 1 1 28489 3 f pm T Vg ian ier Ba eee a Fig 6 61 Ma
324. nents of control valve assembly 5 Lift or slide separator plate 29 off oil transfer plate 7 Note check ball locations in the oil transfer plate fig 6 19 Make a sketch or list that will identify the ball sizes and locations for reassembly Remove the balls NOTE If balls are accidentally lost dropped or misplaced refer to PARTS CATALOG SA 1268 for proper location 6 Remove the lubrication pressure regulator valve from the oil transfer plate as follows Depress cup washer 4 B Lfoldout 20 and remove 5 Release washer 4 and remove it Remove spring 3 and valve 2 Remove valve pin 6 from the oil transfer plate NOTE Before removing p i n s 27 79 82 103 and 109 make a note or sketch that shows the position of adjusting rings 26 78 88 97 102 and 108 in respect to their retaining p i n s If the valve body is reassembled with t h e same springs and the adjusting rings are in their original positions the original calibration of the valve body is maintained W Paani v i x 4 j 7 n i me ue SEE c j a d r 13 E 16 a Pi p ri P y 1 zs H Fi P i pi C zr Y i n B Lj B T T 7 4 4 3 q er ib i223 a i an e 14 i d gue LT sE I2 5421 Fig 6 19 Ball locations in oil transfer plate 7 Disassemble the modulator valve body removed in 3 above Press adjusting ring 22 or 26 inward and remove retainer
325. netary connecting drum also rotating at the same speed the transmission output shaft being splined to the low carrier will produce an output ratio of 1 00 1 Copyright 1983 General Motors Corp 2 35 HT 740D HT 750D AUTOMATIC TRANSMISSIONS TORQUE CONVERTER FOURTH CLUTCH THIRD CLUTCH gt Ea 0 FORWARD CLUTCH 2 FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON SECOND CLUTCH FIRST CLUTCH 7 LOW CLUTCH rem LOW PLANETARY CARRIER CLUTCH PISTON REAR PLANETARY CARRIER CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON Ej CLUTCH APPLIED L b TORQUE PATH 52962 Fig 2 14 Reverse gear torque path 750CRD HT 754CRD i Reverse Gear Operation f i g 2 14 Engine torque is transmitted through the torque converter as described in a above Reverse gear is the only gear in which the forward clutch is not engaged In this gear the fourth clutch is applied and rotates the sun gear shaft via the fourth clutch housing at input speed The low clutch is also applied and anchors the lowring gear against rotation In turn the low ring gear rear carrier center carrier and connecting drum are splined together to form one sta tionary unit When the center sun gear rotates it causes the pinions in the center carrier to rotate in the opposite direction This rotates the c
326. ng 23 Output shaft 24 Speedometer drive gear 25 Spacer sleeve 36 First and reverse clutch trimmer valve 3 Trimmer plug 38 Trimmer valve secondary spring 39 Trimmer valve primary spring 40 First clutch trimmer valve stop 41 Second clutch trimmer valve 42 Trimmer plug 43 Trimmer valve secondary spring 44 Trimmer valve primary spring 45 Second clutch trimmer valve stop 46 Trimmer boost accumulator stop 47 Trimmer boost accumulator valve spring 48 Trimmer boost accumulator valve 49 Trimmer valve cover 50 Bolt 1 4 20 x 5 8 8 A 51 Fourth clutch trimmer valve 52 Trimmer plug 53 Trimmer valve secondary spring 54 Trimmer valve primary spring 59 Fourth clutch trimmer valve stop 56 Retainer pin 57 Retainer 58 2 8 3 4 relay valve fig 2 3 3 4 relay valve spring 60 2 3 3 4 relay valve stop 61 1 2 2 3 relay valve 62 1 2 2 3 relay valve 63 Valve spring spacer 64 Governor screen assembly 65 Pipe plug 1 8 B 66 Governor accumulator valve 67 Governor accumulator valve spring 68 Governor accumulator valve stop 69 Retainer pin 70 Special bolt assembly HT 750 C Gear range designations in parentheses are for HT 750 others are for HT 740 26 Output shaft assembly HT 750DRD 27 Orifice plug 28 Output shaft and bushing assembly 29 Bushing 30 Output shaft 31 Self locking nut 2 16 C 32 Dust shield 33 Lip type oil
327. ng or o therindications of deterioration See Saction 4 8 3 SPRING DATA a Springs must be clean to permit effective inspection Springs should be replaced if there are signs of overheating wear due to rubbing adjacent parts or permanent set Discard springs which do not meet the load height specifications in the spring chart b Inspection criteria load vs height and identification characteristics of the springs are presented in Table 8 2 The spring data are keyed to the exploded views foldouts 9 through 23 in the back of this manual NOTE When more than one spring part number is listed for the same location refer to the HT 700 Series Parts Catalog SA 1268 to determine which spring is used in your specific assembly number Copyright 1983 General Motors Corp 8 1 Illustration foldout 10 3 4 4 22 24 B foldout 10 3 5 10 3 7 10 foldout 12 9 11 13 6771072 Part Number 23011093 6833972 23010437 23010300 23016957 6772462 6837167 23011393 6881898 6838360 9417722 6772293 6839665 or 6834738 6880834 6771084 6834739 or 6838844 6839665 or 6834738 6880834 6834979 6834739 or 6838844 6773625 HT 740D HT 750D AUTOMATIC TRANSMISSIONS Table 8 1 WEAR LIMITS Description TORQUE CONVERTER AND LOCKUP CLUTCH Piston face wear Plate thickness Plate thickness Backplate face wear Backplate face wear Stator assembly TC 470 Stato
328. ns The result is a further change of ratio from t h a t produced in the center planetary Thus the output shaft being splined to the rear carrier rotates at the reduction shown in paragraphl Copyright 1983 General Motors Corp 2 34 DESCRIPTION AND OPERATION LOCKUP CLUTCH TORQUE CONVERTER gt FORWARD CLUTCI T s BUM ETSI ERN A US ER Tmi ELI 1I BR ee FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON 4 THIRD CLUTCH PISTON FOURTH CLUTCH THIRD CLUT i SECOND CLUTCH ys TE m mss spl ne t a im me C M m Er jum i H lu den E m Hh h 1 f ce HAS i n T IUS m er e f Err FIRST CLUTCH LOW CLUTCH LOW PLANETARY CARRIER o FIRST CLUTCH PISTON REAR PLANETARY CARRIER OS CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON E CLUTCH APPLIED e TORQUE PATH 52962 Fig 2 13 Fifth gear torque path HT 750CRD HT 754CRD h Fifth Gear Operation 2 13 Engine torque is transmitted through the lockup clutch as described in b above The forward and fourth clutches are applied With the clutches applied the transmission main shaft and the sun gear shaft are locked together and rotate as a unit at input speed With the center rear and low sun gears rotating at the same speed locked together and their carriers interconnected to the pla
329. nsmission in neutral until normal operating temperature is reached CAUTION If the unit does not have a converter out temperature gage do not stall the converter 6 If normal operating temperature is less than 225 F 107 C shift the transmission to forward range and stall the converter Do not exceed 225 F 107 C 7 As soon as the transmission is cool enough to touch seal all openings and the breather with moisture proof tape VCI 10 is the registered trademark for a vapor phase rust preventive manufactured by Daubert Chemical Company Chicago Illinois VCI 10 is covered by Military Specifications MIL L 46002 ORD and MIL I 23310 WEP under the designation of Nucle Oil Biobor JF is the registered trademark for a biological inhibitor manufactured by U S Borax and Chemical Corporation Copyright 1983 General Motors Corp PREVENTIVE MAINTENANCE 8 Coat all expose unpainted surfaces with preservative grease such as petroleum MIL C 1 1796 Class 2 9 If additional storage time is required repeat steps 2 through 8 at yearly intervals except it is not necessary to drain the transmission each year Just add VCI 10 and Biobor JF or equivalents e Restoring Transmission to Service 1 breather 7 2 spirits 3 If the transmission is new drain the residual preservative oil Refill the transmission to the proper level with Dexron or Dexron ll transmission fluid 4 If the transmission
330. nstall lockup shift valve 8 small end first into the bore indicated in A Be sure the valve will move freely of its own weight in its bore 5 Install spring 9 and valve stop 10 Place washer 11 on spring 9 and compress the spring into the valve bore until the snapring groove is clear Install snapring 12 Copyright 1983 General Motors Corp 6 19 HT 740D HT 750D SERIES TRANSMISSIONS 6 Install spring 13 into the converter regulator valve bore indicated in Aj foldout 134 Install converter bypass valve 1 and valve seat 15 7 Install support assembly 16 and snapring 19 into the valve bore 8 Place converter housing 16 Bj foldout 10 on the work table front side downward 9 Place front support gasket 17 onto the converter housing Align holes in the gasket with those in the converter housing 10 Install front support assembly 1 A foldout 13 onto converter housing 16 B foldout 10 11 Install three 3 8 16 x 2 1 2 inch bolts into the front support fig 6 22 Tighten the bolts to 36 43 Ib ft 49 58 N m 12 Install one 3 8 16 x 1 1 2 inch bolt into the hole between the two valve bores that are closer to each other fig 6 22 Tighten it to 36 43 Ib ft 49 58 N m 13 Install fifteen 3 8 16 x 1 1 2 inch bolts into the outer bolt circle of the front support fig 6 22 Tighten the bolts to 36 43 Ib ft 49 58 N m 14 Install the bearing race flat side first onto the front support hu
331. nted at the top rear of the dropbox at the bottom rear bottom front or any combination of these output positions Copyright 1983 General Motors Corp 2 14 DESCRIPTION AND OPERATION 2 31 HYDRAULIC SYSTEM NOTE Unless otherwise specified all of the hydraulic functions explained ui ae an Miam 5 6 7 and 8 are common to the HT 740D HT 747D HT 750CRD HT 754CRD and the HT 750DRD a System Functions The hydraulic system generates directs and controls the pressure and flow of the hydraulic fluid within the transmission hydraulic fluid transmission oil is the power transmitting medium in the torque converter Its velocity drives the converter turbine lts flow cools and lubricates the transmission and its pressure applies the clutches b System Schematics Color coded foldout illustrations of the hydraulic system are presented at the back of this manual foldouts 5 6 7 8 Each illustration represents the system as it would function during neutral operation and with the engine idling c Oil Filter Pump Circuit foldouts 5 6 7 8 1 Oil blue is drawn from the sump transmission oil pan through a fine mesh filter screen by the input driven pump assembly 2 The oil red is discharged by the input pump through an external filter when so equipped and into the bore of the main pressure regulator valve 3 For models equipped with a hydraulic retarder the oil is discharged from two se
332. o angle eae harnesses are necessary Use Harness assembly Part No 005383 NOTE Make sure that wire is passed through the small hole in the rubber Wire sup pport a as shown c Te Install 1 bushing Part No 004653 onto harness and thread into cylinder head rim Tighten bushing until It has seated to prevent oil leakage NOTE Make sure that excess wire is pushed through the bushing before tightening so that there is no possibility of entanglement with or fuel rack UU NER nm D washer and clamp from the Remove the capscrew supply housing Attach to wire and reinstall Attach spade connection to solenoid valve L DUM P m Be Popa os ai E z ppn Um k amma T TEE TEE m E FM P Te al Place Jacobs rocker cover spacer on cylinder head The spacer Is required to provide for the additional height of the Brake Install PRON cover hold Ec extensions to the cover NOTE On two valve Engines where Jacobs round cover studs replace the original hex studs hold 2 extensions are not Check rocker cover gasket and replace if necessary Position rocker cover over hold down studs and assemble cover to engine NOTE Detroit Diesel Allison Division of General Motors has released die cast aluminum valve covers for use on their series 71 and 92 engines These valve covers and the Jacobs valve cover spacers are not c
333. o fall out pa during handling of the assembly T 3 1 ee ii M 2 Install the control valve assembly as 19 20 x MM assembled onto the transmission using the CON eor S rr M en 7 guide screws as support The groove in the selector VALVE EM valve must engage the on the detent lever 3 Install the lubrication check valve iode a PM 4 po baffle and_retain it with two 1 4 20 x 1 1 2inch bolts on E ee Wd ki giat g marked A fig 7 50 TRANSFER ds WA suc 4 Install two 1 4 20 x 1 1 2 inch bolts B i oo E and two 1 4 inch washers through the oil transfer plate UA vc Boye X and into the transmission Pre nee te 31983 Fig 7 50 Valve body bolt locations Copyright 1983 General Motors Corp 7 27 HT 740D HT 750D AUTOMATIC TRANSMISSIONS housing Bolts A and B retain the oil transfer plate Eco 4 um m separator plate and control valve assembly to the x transmission housing fig 7 50 CT ges coge b Install thirteen of fifteen 1 4 20 x 3 lt 14 inch bolts C earlier models use two additional bolts he replaced in later models by two bolts D at the lower ef positions in fig 7 50 through the control valve body assembly into the housing Remove the two guide screws and install the two remaining C bolts Install three earlier models use only one bolt at the top hole 1 4 20 x 3 1 2 inch bolts D into the center of the valve body fi
334. o the hole nearer the differently Refer to item 3 for center of the valve body The hole installation of the filter with a six near the end of the valve body must inch deep oil pan item 4 for a remain open seven inch deep pan and item 5 for an eight and one half inch deep pan 3 Retain oil filter 33 B Lfoldout 16 with one 5 16 18 x 1 5 8 inch bolt and one Copyright 1983 General Motors Corp 7 28 ae ire a wu T Sigg Fig 7 52 Installing oil pan 5 16 plain washer fig 7 52 Later models use one 5 16 18 x 1 5 8 inch bolt and one spacer 32 located on the bolt between the oil filter and the valve bogy Tighten the screw to 17 20 lb ft 23 27 Nem 4 Retain oil filter 24 A foldout 17 with one 5 16 18 x 2 3 4 inch bolt one 5 16 plain washer and two spacers 27 Tighten the screw to 17 20 Ib ft 23 27 Nem 5 Retain oil filter 22 B foldout 17 with three 5 16 18 x 3 1 4 inch bolts Tighten the bolts to 17 20 Ib ft 23 27 Nem 6 Install two 5 16 18 x 38 inch guide screws J 3387 2 into the transmission housing fig 7 52 7 Install a new oil pan gasket over the guide screws Align all holes in the gasket with those in the housing fig 7 52 CAUTION Do not apply grease to a cork gasket A cement or sealer may be applied only in the area outside the raised bead on the oil pan flange ASSEMBLY OF TRANSMISSION ode k eo OIL PAN 3 Fig 7 53 Installing
335. octite 40 Retaining Compound or equivalent onto the collar of the collector ring Install the collector ring fig 6 41 Use installer COLLECTOR RING PRESS TO SHOULDER AND BEND METAL INTO GROOVE FOR ENTIRE CIRCUMFERENCE FORWARD CLUTCH HOUS ING MUST WITHSTAND 3018 133 45 N LOAD APPLIED IN THIS DIRECTION TURBINE SHAFT 9437 Fig 6 40 Forward clutch housing partial cross section view gr is i Ei pep tici iil VS nicer Sd Cpu EE Fig 6 41 Installing pitot collector ring J 24200 2 to drive the collector ring onto the clutch housing fig 6 41 Use light hammer blows and work around the entire installer circumference b Using staking tool J 24200 1 bend the edge of the ring into the groove in the clutch housing Check the four steel balls in the housing Make sure they are securely staked in the housing and are free to move without restriction Copyright 1983 General Motors Corp 6 30 REBUILD OF SUBASSEMBLIES Fig 6 42 Staking pitot collector ring to forward clutch housing 6 This procedure and 7 and 8 following apply to earlier models If collector ring 6 was removed replace it with a new ring Refer to items 4 and 5 above 7 Install PTO gear snapring 8 foldout 13 into its groove on the outside diameter of the forward clutch housing 8 Install PTO gear 9 chamfered ends of the internal splines first onto the forward clutch housing The chamfered end
336. odels contain t e n clutch plates a clutch piston housing and a piston Five plates are internally splined and five are externally tanged The piston is positioned inside the clutch housing in its bore and retained by twenty piston return springs a spring retainer and a snapring c Operation A foldout 14 All models 1 Internal splined clutch plates 4 driven by fourth clutch driving hub 22 B foldout 13 rotate any time the input shaft and the forward clutch housing assembly rotates Copyright 1983 General Motors Corp 2 6 DESCRIPTION AND OPERATION 2 When hyaraulic pressure is directed to the back side of fourth clutch piston 9 foldout 14 the piston compresses clutch plates 4 and 5 together This locks internal splined plates 4 to external tanged plates 5 and in turn to clutch housing 14 3 Since center sun gear and shaft assembly 23 Woda or B foldout 15 A foldout 16 is splined to the clutch housing it will also rotate at input speed 2 13 SECOND THIRD CLUTCHES AND CENTER SUPPORT Bj foldout 14 a Function Differs Among Models 1 The second and third clutches in the HT 740D and HT 747D perform only one function When engaged simultaneously with forward clutch the second clutch produces second gear while the third clutch produces third gear 2 The second and third clutches in the HT 750CRD HT 754CRD and HT 750DRD perform only one function When engaged w i t h forward clutch
337. of the vehicle and its travel path The main pressure regulator valve spring is under approximately 85 Ibs 378 N compression Do not install forward clutch hub 19 B foldout 13 a n d fourth clutch driving hub 22 into fourth clutch housing assembly 12 A foldout 14 If these two hubs are installed into the fourth clutch housing assembly by mistake the transmission will operate in reverse when the driver selects any forward range Be sure the forward clutch hub and the fourth clutch driving hub are installed into the forward clutch assembly as shown in figure 6 45 If these t w o hubs are installed into the third clutch housing by mistake the transmission will operate in reverse when the driver selects any forward range Copyright 1983 General Motors Corp SA 1270J Service Manual Allison Transmissions AUTOMATIC MODELS HT 7400 HT 7470 750CRD HT 754CRD HT 750DRD HT 750DRD DB HT 754CRD REVISED DECEMBER 1983 Y Detroit Diesel Allison Division of General Motors Corporation indianapolis indiana 46206 Printed ia U S A 1983 General Motors Corp NOTE This publication is revised periodically to include improvements new models special tools and procedures Revision is indicated by letter suffix to publication number Check with your Detroit Diesel Allison service outlet for currently applicable publication Additional copies of this publication may be purchased from authorized Detroit Diesel Allison se
338. oil filter in the line from the oil cooler is recommended This recommendation applies whether the failed transmission is overhauled or replaced by a new or rebuilt unit The auxiliary filter must have a 40 micron particle filtering capacity and a maximum pressure drop of 2 psi at 15 gom The maximum pressure drop in the cooler circuit must not exceed 30 psi at 15 gpm at operating temperature and at full throttle stall The following filter assemblies and filter elements are recommended Filter Assembly Filter Element AC PM 13 7 PF 132W AC PM 13 15 PF 911 Auxiliary filter elements should be monitored for contamination after 500 1000 hours operation depending on application and changed at regular filter change intervals thereafter NOTE Retarder equipped transmissions should have the heat exchanger replaced or disassembled and thoroughly cleaned Installing a filter in the cooler return line generally is unsatisfactory because of the size required to handle the flow and not increase the external circuit pressure drop above specified maximum limits 3 8 BREATHER The breather is located at the top of the transmission housing as shown in figure 1 2 The breather prevents pressure buildup within the transmission The breather must be kept clean and the passage open The prevalence of dust and dirt will determine the frequency at which the breather requires cleaning Always use a wrench of the proper size to remove or repla
339. oil pan screws 8 Install the oil pan fig 7 53 Install twenty three 5 16 18 x 5 8 inch washer head screws to retain oil pans 41 B foldout 16 and 29 A foldout 17 Install twenty three 5 16 18 x 4 3 4 inch bolts to retain oil pan 29 B Tighten the screws evenly to 17 20 Ib ft 23 27 Nem NOTE To prevent leakage pan screws must retain a 5 16 ft 7 Nem minimum torque after gasket set 7 17 INSTALLING VALVE BODIES FILTER OIL PAN HT 750CRD HT 754CRD HT 750DRD DRD DB Valve Bodies 1 Install two guide screws J 24315 3 into opposite holes in the transmission housing 54 2 Install the control valve assembly as assembled in para 6 6 using the guide screws as support onto the transmission The groove in the selector valve must engage the pin on the detent lever Copyright 1983 General Motors Corp 7 29 ge i Peary ee 1 d D i T Y T z m hu SEPARATOR PLATE g a audio di C 2 EE IN E T Di a ie Tec zc j FLA LUBRICATION DOS EE fer VALVE ii ff 1 CONTROL VALVE JR al ASSEMBLY 7 j 2815 3 4 X3 4 2 Ri ore I a Y TRI HET d MET fo UM i DE Dome prd Lob 9 Lt ads de a ys n p ard uxo 1 SES aT TKF zi a T s E FRE n GET ET E a des sur E EU i T 9 gt
340. ompatible Detroit Diesel has also released deep die cast covers for Jacobs Engine Brake installations Only the Detroit Diesel stamped valve covers can be used with Jacobs valve cover spacers CONTROL SYSTEM INSTALLATION Buffer Switch Installation Remove buffer screw from govemor YE ng and remove lock nut from buffer screw Separate buffer switch as shown in photo Do not loosen the switch mounting screws This switch has been pre set at the factory to insure that the Engine Brake will not operate while fuel is being supplied to the engine Field replacement of the micro switch or diode if necessary requires the use of an adjusting gauge to re adjust the switch to factory standards This adjusting gauge Part No 2859 is capable of adjusting three different style switches Part Nos 2732 2733 and fast idle switch 2808 ADJUSTMENT PROCEDURE 1 Insert thread portion of butter screw into open end of the tool until buffer spring is nearly in contact with the plunger 2 Tighten locknut so that tool is tight on the buffer screw and will not rotate 3 Push the plunger in so that it rests on but does not compress the buffer spring Tighten thumb screw to lock plunger in position 4 Attach switch loosely to mounting bracket Move switch in until it clicks on then back out until switch clicks off 5 Holdthis position and tighten switch mounting screws 6 If switch is mounted correctly a 010 25 mm feeler gauge inserted between
341. on housing First eluteh Adapter housing assembly Low eluteh Rear eover assembly Governor drive gear Speedometer drive gear Output shaft Output flange retainer nut Governor assembly Low planetary carrier assembly Rear planetary earrier assembly Gear unit connecting drum Low shift valve assembly Low trimmer valve assembly Center planetary earrier assembly Front planetary earrier assembly Oil pan Cover plate PTO drive gear Pitot tube Retarder plate assembly Seavenge pump assembly PTO and seavenge pump drive gear Input shaft Flywheel HT 740D HT 750D AUTOMATIC TRANSMISSIONS Foldout 3 Model HT 750DRD transmission cross section view Copyright 1983 General Motors Corp 21 25 26 27 28 FOLDOUT 3 E O09 OAD Dow m C o OT Don bo M Bo gt C Starter ring gear Loekup eluteh Torque converter turbine Torque converter stator Torque converter pump PTO accessory cover PTO idler gear Transmission input pump Torque converter housing Retarder housing Retarder rotor Forward support and valve assembly Pitot collector ring Forward eluteh assembly Fourth eluteh assembly Third eluteh assembly Center support housing assembly Main shaft assembly sun gear and shaft assembly second eiuteh Transmission housin First eluteh Adapter housing assembly Low cluteh Transfer gear housing dropbox adapter Transfer ge
342. ooks and distortion Replace all composition gaskets 4 Install a new hook type sealring if the ring shows any wear on the outside diameter or if there is excessive side wear b The sides of the sealring must be smooth 0 005 inch 0 13 mm maximum side wear The sides of the shaft groove or the bore in which the sealring fits should be smooth 50 microinches 1 27 micrometers equivalent and square with the axis of rotation within 0 002 inch 0 05 mm If the sides of the grooves have to be reworked install a new sealring 6 Inspect clutch housing sealring surfaces for nicks burrs dents or displaced metal that could interfere with mating parts Copyright 1983 General Motors Corp 4 12 GENERAL OVERHAUL INFORMATION or damage the piston seal Remove raised metal sharp edges burrs or nicks with a soft stone and crocus cloth Thoroughly clean all residue from housing prior to assembly 7 Inspect sealring grooves in the piston for nicks burrs dents or displaced metal that could damage the seal Remove raised metal sharp edges burrs or nicks with a soft stone and crocus cloth Thoroughly clean all residue from the piston prior to assembly IN Inspecting Gears 1 Inspect gears for scuffed nicked burred or broken teeth If the defect cannot be removed with a soft stone replace the gear 2 Inspect gear teeth for wear that may have destroyed the original tooth shape f this condition is found re
343. ooves on the front support hub Insert do not force gage J 29198 3 into a groove on the support hub Rotate the gage 360 degrees around the hub f the gage does not rotate freely the support is damaged and should be replaced NOTE Refer to above b Assembly NOTE When bearing installer J 24197 is not available the depth of installation must be measured Proper depth from the rear of the hub to the rear of the bearing is 1 26 to 1 28 inches 32 32 5 mm 1 If the needle bearing was removed from the front support fig 6 26 install a new bearing Installer J 24197 may be used with handle J 8092 for driving the bearing or without the handle when press installing the bearing Drive or press on the numbered side of the bearing NOTE Installation of the main pressure regulator and lockup shift valves as described in 2 through 5 below is done with the aid of spring compressor J 24219 The spring compressor is not required for installation of the converter regulator valve described in 6 and 7 below Fig 6 26 Tool for installing front support needle bearing 2 Install main pressure regulator valve 3 small end first into the bore indicated in A foldout 13 Be sure the valve will move freely of its own weight in Its bore 3 Install spring 4 and valve stop 5 Place washer 6 on spring 4 and compress the spring into the valve bore until the snapring groove is clear lis 6 25 Install snapring 7 4 I
344. or to S N 10300 36 Install stop bolt 70 when valve 81 is used into control valve assembly The flat end of the bolt must align with the flat side of the selector valve 21 Tighten the stop bolt to 36 43 Ib ft 49 58 N m NOTE Refer to paragraph 3 12 for the adjustment of shift speed points 37 To prevent dust or dirt from contaminating the valve assembly place it in a plastic bag until ready for installation into the transmission 6 7 LOW TRIMMER VALVE BODY ASSEMBLY HT 750 a Disassembly A foldout 21 1 Press inward on retainer plug 26 and remove retainer pin 20 2 Release pressure and remove plug 26 springs 23 and 24 valve stop 25 plug 22 and valve 21 NOTE Refer to above Copyright 1983 General Motors Corp 6 15 HT 740D HT 750D SERIES TRANSMISSIONS b Assembly A foldout 21 1 Install low clutch trimmer valve 21 recessed end first into valve body 19 NOTE Valves when installed dry should move by their own weight 2 Install trimmer plug 22 3 Install springs 23 and 24 valve stop 25 and retainer plug 26 4 Compress springs 23 and 24 and install retainer pin 20 to secure plug 26 6 8 LOW SHIFT VALVE BODY ASSEMBLY HT 750 a Disassembly A foldout 21 1 Depress valve stop 9 against its spring and remove retainer pin 5 NOTE In earlier models valve stop 9 consisted of t w o separate pieces 2 Release spring pressure and remove valve stop 9 s
345. orque converter Oil must flow through the converter continuously to keep it filled and to carry off the heat generated within the converter 2 Converter out oil orange leaving the torque converter is directed to an external cooler supplied by vehicle or engine manufacturer When the transmission includes a hydraulic retarder converter out oil flows through the retarder control valve before going to the cooler A flow of air or water over or through the cooler removes the heat from the transmission oil Copyright 1983 General Motors Corp 2 15 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 3 On models having no hydraulic retarder lubrication oil green is directed through the transmission to components requiring continuous lubrication and cooling The lubrication oil then drains into the sump Oil in excess of that required by the lubrication circuit escapes to the sump through the lubrication regulator valve 4 Lubrication oil on the retarder equipped models originates in the second section of the input driven pump para c above The oil black and green leaving the pump is directed to the 0 250 orifice and the lubrication regulator valve The oil green passing through the 0 250 orifice is directed to transmission components requiring continuous lubrication and cooling Oil in excess of that required by the lubrication circuit escapes through the lubrication regulator valve into the converter in circuits Excess supply
346. orward clutch hub 19 9 Remove bearing race 18 and needle bearing 17 from the inner hub of the forward clutch hub fig 6 37 10 Remove bearing race 16 from the inner hub of the forward clutch housing fig 6 37 11 Using spring compressor 21 J 24204 3 compress the spring retainer Remove the snapring 6 38 12 Carefully remove pressure from the spring retainer Remove the spring retainer 13 Remove twenty piston return springs 13 TETTE 13 14 Remove forward clutch piston 12 and sealrings 10 and 11 If a sealring is used in the clutch housing remove and discard it 15 If the piston is replaced be sure the identification letter A B or C for the new piston is identical to that of the piston replaced 1968 Fig 6 37 Forward clutch components Copyright 1983 General Motors Corp 6 28 REBUILD OF SUBASSEMBLIES S295 Fig 6 38 Removing or installing forward clutch spring retainer snapring 16 Do not remove the PTO gear unless replacement is necessary 17 To remove the earlier type PTO gear slip fit on housing refer to 18 to 21 below To remove the later type PTO gear press fit on housing refer to 22 to 26 below 18 Remove collector ring 6 only if damage has occurred Support the inner circumference of the ring and press the forward housing and input shaft assembly free 19 Remove the PTO gear by compressing the snapring into the clutch housing and sliding
347. osition install six 3 8 16 x 4 inch bolts replacing guide bolts with last two Refer td figure 6 31 for location of bolts Tighten the bolts to 36 43 Ib ft 49 58 Nem 12 Lubricate sealring 1 B foldout 12 with oil soluble grease Install the sealring into the groove around the retarder plate Copyright 1983 General Motors Corp REBUILD OF SUBASSEMBLIES 13 If the three studs at the rear of the converter housing were removed install new studs oversizes are available if required 14 Select studs which when installed to project 5 47 to 5 53 inches 138 94 to 140 46 mm will tighten to 15 65 Ib ft 20 88 Nem 6 13 CONVERTER HOUSING WITH 8 BOLT TOP COVER FRONT SUPPORT OIL PUMP a Disassembly 1 Refer 6 10a 1 through 5 for removal of the oil pump 2 Refer to 6 10a 6 through 11 for removal and disassembly of the front support assembly 3 Refer to paragraph 6 12a 5 J 7 8 10 and 11 for the remaining disassembly steps NOTE Refer to above b Assembly 1 Refer to para_6 10b 1 through 7 for assembly of the front support components 2 Refer to 6 12b 1 2 3 4 6 and 7 for initial assembly of the converter housing components 3 Position the housing front downward Install the front support gasket and align its holes with those of the converter housing 4 Install the front support assembly and retain it with sixteen 3 8 16 x
348. ost accumulator stop 46 B aident 20 spring 47 and trimmer boost accumulator valve 48 into bore S fig 6 20 of valve body 30 8 Place trimmer valve cover 49 B foldout Compress the springs and retain the cover with eight 1 4 20 x 5 8 inch bolts 50 Tighten the bolts to 9 11 Ib ft 12 15 Nem 9 Install trimmer regulator valve 114 smaller diameter first spring 115 and valve stop 116 into bore G of valve body 30 B Toldout 20 Depress the valve stop and insert retainer pin 117 into its hole in the valve body NOTE In earlier models valve stop 112 consisted of two separate pieces 10 Install relay valve 110 spring 111 and valve stop 112 into bore H fig 6 20 of valve body 30 B foldout 20 Depress the valve stop and insert retainer pin 113 into the hole at the front of the valve bore 11 Install shift valve 104 smaller end first modulator valve 105 smaller end first spring 106 valve stop 107 and adjusting ring 108 flat side first into bore I of valve body 30 B foldout 20 12 Align the pin hole in valve stop 107 with the pin holes in the valve body Compress the spring and install retainer pin 109 into the valve body to retain adjusting ring 108 Be sure the adjusting ring is in the same position as it was before removal 13 Install shift valve 98 smaller diameter first modulator valve 99 smaller diameter first spring 100 valve stop 101 and adjusting ring 102 flat side fir
349. ousing and ground sleeve Converter housing models with retarder no PTO Scavenge oil pump and power takeoff driven gear Retarder and retarder housing Front support and valve assembly 13 Forward clutch assembly Fourth clutch assembly Third clutch center support and second clutch Gear unit and main shaft assembly HT 740D HT 747D Gear unit and main shaft assembly HT 750CRD HT 754CRD Gear unit and main shaft assembly HT 750DRD Transmission housing oil filter and six inch deep oil pan Transmission housing oil filter and seven inch oil pan Transmission housing oil filter and eight and one half inch oil pan First clutch Adapter housing low clutch plates and low carrier HT 750CRD HT 754CRD Adapter housing low clutch plates and low carrier HT 750DRD Low clutch piston rear adapter housing and governor First and low piston rear cover output shaft and governor Control valve assembly Lockup cutoff low shaft and low trimmer valve body assemblies Retarder valve body assembly Transfer gears and transfer gear driven shaft 22 Transfer gear housing Rear output disconnect clutch 23 Front output disconnect clutch Copyright 1983 General Motors Corp Section 1 GENERAL INFORMATION 1 1 SCOPE OF MANUAL a Coverage This Service Manual describes the operation maintenance and overhaul procedures for the HT 700 oeries automatic Fa o oue TES The major components of the transmission are explained
350. ousing is mounted between main housing 8 foldout 16 and rear cover 8 foldout 20 in the straight through models c n transfer gear housing models the rear adapter housing is covered by transfer housing adapter linen 9 ji foldout 19 and transfer gear housing 6 Bj foldout 22 2 27 REAR COVER foldout 20 Rear cover 14 is made of cast iron and machined to receive governor assembly 38 and first or low clutch piston 4 The rear cover provides support for output shaft assemblies 19 or 26 A parking brake mounting face is also provided on the rear surface The cover is the rear closure member and is attached to either the transmission housing HT 740 747 models or the adapter housing HT 750 models b y twenty four bolts 17 and 36 2 28 TRANSFER GEAR HOUSING ADAPTER Transfer gear housing adapter assembly 9 B foldout 19 is made of cast iron and machined to receive governor assembly 26 and low clutch piston 5 An oil seal is installed in the rear of the housing to keep the oil in the front section from mixing with a different grade of oil used in the dropbox 2 29 TRANSFER GEAR HOUSING DROPBOX B The dropbox housing contains a drive gear at the top an idler gear in the center and an output driven gear at the bottom Rotation of the drive gear and the output driven gear are in the same direction The input output ratio is 1 00 1 2 30 MANUAL DISCONNECT CLUTCH A A manual disconnect clutch can be mou
351. ousings to the transmission housing one bolt removed when holding fixture was installed fig 5 1 Remove three nuts 56 and three washers 57 3 Attach a three strand lifting sling to the converter housing and carefully separate the converter housing and retarder housing being careful that the retarder housing is not lifted from the transmission housing If the retarder housing is lifted the pitot tube and or oil collector ring can be damaged When free remove the converter housing Refer to for rebuild of the housing assembly 5 10 REMOVING RETARDER VALVE BODY HOUSING AND FRONT SUPPORT AND SLEEVE ASSEMBLY a Retarder Valve Body Assembly 1 Remove four 3 8 16 x 2 5 8 bolts 2 B foldout 21 and four 3 8 lockwashers 1 2 Remove two 3 8 16 x 3 3 4 bolts 4 and two lockwashers 3 Remove two 3 8 16 x 4 3 4 bolts 6 and two 3 8 lockwashers 5 3 Remove valve body assembly 9 and gasket 8 Refer to paragraph 6 15 for rebuild of the retarder valve body assembly b Retarder Housing and Front Support and Sleeve Assembl NOTE Item 6 7 8 B may have adhered to the housing assemblies removed in or d If so remove them 1 If not previously removed remove thrust race 6 12 roller bearing 7 and thrust race 8 from retarder rotor assembly 10 2 Remove the retarder rotor assembly 5 33 Remove thrust race 12 foldout 12 bearing 13 and thrust race 14 3 Remove the sealrings from the front and
352. ove depth REAR COVER OUTPUT SHAFT AND GOVERNOR Rear cover clearance of governor bore to governor Output shaft bushing clearance on main shaft 34 A foldout 15 34 B fold out 15 34 A foldout 16 Minimum depth of oil grooves 0 008 inch 0 20 mm Copyright 1983 General Motors Corp 8 5 Wear Limit in mm 0 1347 3 421 0 1347 3 421 0 1347 3 421 0 090 2 29 0 1347 3 421 0 1347 3 421 0 1347 3 421 0 0993 2 522 0 013 0 33 0 1161 2 949 0 013 0 33 0 090 2 29 0 1347 3 421 0 1347 3 421 0 1347 3 421 0 993 2 522 0 013 0 33 0 1161 2 949 0 013 0 33 0 0068 0 173 0 090 2 29 0 004 0 10 0 004 0 10 Fold Ref r E DW gt pp po 2 UJ UJ gt UJ gt Sn UJ 10 56 11 13 14 21 5 Spring Stator freewheel Lubrication valve Lubrication valve Main regulator valve Lockup shift valve Converter bypass valve Forward clutch piston release Fourth clutch piston release Third clutch piston release second clutch piston release First clutch piston release Mean dimension shown HT 740D HT 750D AUTOMATIC TRANSMISSIONS Part No 6775852 6837882 6837882 6839209 6830166 6838089 6838090 6838520 6839268 6839419 6769252 6836138 6836138 6831656 6831656 6831656 Table 8 2 SPRING DATA Color Code No Color Code No Color Code No Color Code No Color Code oolid green Green stripe Solid white Solid blue Blue stripe oolid orange oolid gr
353. ove the snapring that retains second clutch plates fig 5 41 2 Remove 13 second clutch plates of which seven are external tanged and six are internal splined plates NOTE Tie the second clutch plates together and identify the pack Retain for inspection 5 13 REMOVING REAR COMPONENTS HT 740D 7470 A foldout 20 a Governor A foldout 20 1 If the governor was not previously removed proceed as follows 2 Position the transmission rear upward 3 Remove four bolts 43 A foldout 20 4 Remove cover 42 and gasket 41 Fig 5 41 Removing second clutch snapring 5 Rotate governor assembly 38 clockwise then remove it 6 Refer td paragraph 6 31 for rebuild of the governor assembly b Rear Cover 1 Remove twenty four bolts and washers that retain the rear cover to the transmission housing fig 5 42 2 Attach a lifting sling to the rear cover and remove the cover from the transmission housing 43 Remove the gasket 3 Refer tq paragraph 6 26 for rebuild of rear cover assembly c First Clutch 1 Remove two external tanged clutch plates and one internal splined clutch plate fig 5 43 2 Remove the rear planetary ring gear 5 43 3 Remove the ten remaining first clutch plates from the rear of the transmission housing WASHER 3 F wx BEAR COVER T a i n 2 CR UM LL 2 Lr By c E TN n FU i it G n gt
354. ownward so the PTO gear is resting on the cylindrical fixture Center the fixture directly under the PTO gear 26 Center fixture tool J 26899 1 inside the forward clutch housing and apply Copyright 1983 General Motors Corp 6 29 HT 740D HT 750D SERIES TRANSMISSIONS sufficient pressure to the tool to remove the PTO gear Hemove the snapring CAUTION Pressure applied directly to the turbine shaft will cause permanent damage 27 Do not remove balls 7 from the forward clutch housing unless replacement is necessary NOTE Refer to above b Assembly B foldout 13 NOTE Early and late models differ in P T O installation On current models use procedures 1 through 5 below On earlier models use procedures 6 through 8 1 This procedure and 2 through 5 following apply to current models Place forward clutch housing 5 on a work table shaft end downward Install snapring 8 into the groove on the outside diameter of the housing 2 Heat PTO gear 9 in an oven or an oil bath to 3500 to 3750F 1770 to 19100 3 Carefully install the PTO gear onto the forward clutch housing chamfer end first unt i 1 the snapring expands into the PTO gear groove Make sure the snapring is expanded and free in the internal groove of the gear before the gear cools Failure to obtain this condition can result in difficulty during subsequent removal 4 Position the forward clutch housing turbine shaft upward Apply L
355. para 3 3 Check the valve body mounting bolts Reroute or replace as necessary Replace valve spring Copyright 1983 General Motors Corp 3 22 ID N I pm IA Ir PREVENTIVE MAINTENANCE Table 3 1 TROUBLESHOOTING CHART cont Cause OIL LEAKING INTO CONVERTER HOUSING Converter pump hub seal worn Converter pump hub worn at seal area Engine rear seal worn TRANSMISSION OVERHEATING IN ALL RANGES Oil level low Oil level high Cooler restricted oil or coolant side NO RESPONSE TO SHIFT LEVER MOVEMENT Range selector linkage disconnected service manual Range selector linkage defective or broken Main pressure low Range selector not engaged at control valve ROUGH SHIFTING Manual selector linkage out of adjustment Control valves sticking Modulator valve sticking spring adjustment too tight Modulator actuator cable kinked or out of adjustment DIRTY OIL Failure to change oil at proper interval Heat excessive Clutch failure Damaged oil filter OIL LEAKING AT OUTPUT SHAFT Oil seal at output flange worn or damaged Flange worn at seal surface p ma e 2 Hemedy Replace seal Replace pump hub Refer to engine or vehicle service manual Add oil to proper level Drain oil to proper level Remove restrictions Connect linkage refer to vehicle Repair or replace linkage refer to vehicle service manual Refer to C above Install or replace p
356. paragraph 6 11 for rebuild of the housing assembly c Housing with 8 Bolt Top Cover no retarder 1 Remove the two screws and washers retaining the pitot tube or steel block from inside the converter housing fig 5 29 2 Remove seven bolts and washers from inside the converter housing fig 5 29 p d Fig 5 31 Removing converter housing bolts retarder models Copyright 1983 General Motors Corp 5 13 HT 740D HT 750D AUTOMATIC TRANSMISSIONS TERR 3 ne ii TRANSMISSION HOUSING j eit iE E x ELT THEO 7 ay eee ae j Bad wha ea us L 53763 Fig 5 32 Removing converter housing 3 Remove nine bolts 3 and washers 2 B CEMER retaining the converter housing to the transmission housing two bolts removed when holding fixture was ena TEET 4 Attach a three strand lifting sling fig _5 and remove the converter housing 5 Refer to paragraph 6 13 for rebuild of the converter housing assembly 6 Remove the pitot tube or steel block fig freed in item 1 7 On earlier models if the side PTO spindle must be removed remove the bolt and washers from the rear of the spindle Press the spindle rearward d Housing with 8 Bolt Top Cover with retarder 1 From inside the converter housing remove seven bolts and washers fig 5 31 Hemove seven bolts 63 and washers 62 foldout 16 retaining the converter and retarder h
357. parator plate during handling A slight separation could dislocate the check valve balls and cause malfunction of the transmission 32 Install the assembled modulator valve onto the oil transfer plate as shown in Install three 1 4 20 x 2 1 2 inch bolts to retain the modulator body oil transfer plate separator plate and control valve body assembly as a unit Do not tighten the bolts at this time 33 Align the bolt holes in the control valve assembly with those in the separator plate and oil transfer plate When all bolt holes are aligned tighten the bolts installed in 32 above to 9 11 Ib ft 12 15 N m 34 Install manual selector valve 80 B foldout into bore O fig 6 18 of control valve body 30 Valve 80 may be retained by tape or soft wire temporarily until the valve assembly is installed onto the transmission 35 Before S N 1030 in HT 750 models valve 81 must be positioned so that its flat side is upward when assembly is positioned as in fig 6 21 AT VY Invi VALV E Ae N pes Asa y M rx 7 3x dcs et I ets 3 a LN f XL k is 7 is gs s Lx ut m A S ri rE TR ol P IL Wi i px ri i BESA fa m i dita if yr tit E ad 1 odi i F Lue eas SO b TE T m 1 LU 4 F a porter Pe canal Rae Ur aris Eus Fi F Fig 6 21 Tightening selector valve stop bolt HT 750 pri
358. pin 27 Release the adjusting ring and remove it Remove valve stop 21 washer 20 spring 19 and valve 18 prior to S N 2510066690 After S N 2510066689 remove spring 25 modulator valve 24 and modulator actuator valve 23 8 Remove priority valve 73 spring 72 and valve stop 71 from the control valve body 30 9 Position valve body 30 flat side upward on the work table Remove plug 65 and screen assembly 64 10 Remove eight bolts 50 while holding trimmer cover 49 against spring pressure Relieve pressure and remove cover 49 Copyright 1983 General Motors Corp 6 10 REBUILD OF SUBASSEMBLIES 11 Remove springs 33 and 34 valve stop 35 trimmer plug 32 and trimmer valve 31 12 Remove springs 38 and 39 stop 40 plug 37 and valve 36 13 Remove springs 43 and 44 stop 45 plug 42 and valve 41 14 Remove valve 48 spring 47 and stop 46 15 Remove springs 53 and 54 stop 55 plug 52 and valve 51 NOTE In operations 16 through 24 below the components in each bore are spring loaded and must be compressed while removing the retainer pins 16 Remove retainer pin 56 valve stop 60 spring 59 and valve 58 NOTE In earlier models valve stop 60 consisted of two separate pieces 17 Remove retainer pin 57 spring spacer 63 spring 62 and valve 61 18 Remove retainer pin 69 spring 67 stop 68 and valve 66 NOTE Before S N 10300 remove retainer pin 79 plug s t o p 76 spring
359. place the gear 3 Inspect the thrust face of gears for scores scratches and burs Remove such defects with a soft stone If scratches and scores cannot be removed with a soft stone replace the gear 1 Inspecting Splined Parts Inspect splined parts for stripped twisted chipped or burred splines Remove burs with a soft stone Replace the part if other defects are found Spline wear is not considered detrimental except where it affects the fit of the splined parts Inspecting Threaded Parts Inspect parts for burred or damaged threads Remove burs with a soft stone or fine file Replace damaged parts Inspecting Snaprings Inspect all snaprings for nicks distortion and excessive wear Replace snapring if any of those defects is found The snapring must snap tight in its groove for proper functioning m Inspecting Springs Inspect springs for signs of overheating permanent set or wear due to rubbing adjacent parts Replace the spring if any one of these defects is found Refer to the spring chart at end of Section 8 n Inspecting Clutch Plates 1 Inspect friction faced steel plates internal splined plates for burs embedded metal particles severely pitted faces loose facings excessive wear cone cracks distortion and damaged spline teeth Remove burrs using a soft honing stone Replace plates which have other defects 2 Inspect steel plates external tangled plates for burs scoring excess
360. planetary carrier assembly 4 onto sun gear and shaft assembly 8 12 Install thrust washer 3 sun gear 2 and thrust washer 1 onto sun gear and shaft assembly 8 Copyright 1983 General Motors Corp 6 44 REBUILD OF SUBASSEMBLIES 1 Thrust washer 2 Front planetary sun gear 3 Thrust washer 4 Front planetary carrier assembly 5 Thrust washer 6 Sun gear and shaft assembly 7 Thrust washer 8 Internal snapring 9 Front planetary ring gear 10 Center planetary carrier assembly 11 Main shaft 12 Center planetary ring gear 13 External snapring 14 Thrust race DUM uU 23 A r 1 TY t i e 1 E ue i DJ w 5 1 Bu TENES Js 24 5 2 E a A D ZZ ar I 2 Eu 94 amp F1 Seyi 15 Needle roller bearing 16 Rear planetary sun gear 17 Planetary connecting drum 18 Internal snapring 19 Thrust race 20 Thrust race 21 Needle roller bearing 22 Thrust race 23 Snapring 24 Low planetary sun gear 25 Rear planetary carrier assembly Fig 6 66 Components of gear unit and main shaft assembly HT 750CRD 6 22 GEAR UNIT AND MAIN SHAFT ASSEMBLY HT 750CRD HT 754CRD foldout 15 1 Remove bronze thrust washer 1 from sun gear 2 Remove sun gear 2 and bronze thrust washer 3 a Disassembl 2 Remove front planetary carrier assembly 4 and thrust washer 5 Refer to paragraph 6 23 for rebuild of the carrier asse
361. planetary earrier assembly Center planetary earrier assembly Rear planetary earrier assembly First clutch Adapter housing assembly Low clutch Low carrier assembly Rear cover assembly Governor drive gear Speedometer drive gear Output shaft Output flange retaining nut Gear unit eonneeting drum Low shift valve assembly Low trimmer valve assembly Control valve assembly Oil filter Cover plate Oil pan Pitot tube Flywheel PTO drive gear HT 740D HT 750D AUTOMATIC TRANSMISSIONS Foldout 2 Model HT 750CRD HT 747CRD transmission cross section view Copyright 1983 General Motors Corp ELE 15 mn 53105 FOLDOUT 2 MEME OOND 4 C 00 61 hw wp N Co t2 eo co Q3 Q3 Q2 4 C2 f Co C2 CO 1 C Hm i pm gt Co Co n CO OO gt gt ou DO gt Starter ring gear Lockup clutch Torque converter turbine Torque converter stator Torque converter pump PTO accessory cover PTO idler gear Transmission input pump Torque converter housing Retarder housing Retarder rotor Forward support and valve assembly Pitot collector ring Forward clutch assembly _ Fourth clutch assembly Third clutch assembly Center support housing assembly Main shaft assembly Sun gear and shaft assembly Second eluteh Transmissi
362. plit sleeve bushing 2 Thrust washer 28 Planetary connecting drum 29 External snapping 30 Center planetary ring gear 31 Thrust race 32 Needle roller bearing 33 Thrust race 34 Main shaft assembly 35 Orifice plug 36 Main shaft 3 Rear planetary sun gear 38 Rear planetary carrier assembly 39 Rear carrier and bushing assembly 40 Rear carrier 41 Sleeve bushing 42 Bronze thrust washer 8 43 Pinion 4 44 Needle roller bearing 4 45 Steel thrust washer 8 46 Pinion pin 4 47 Thrust race 48 Needle roller bearing 49 Thrust race 50 Internal snapping 51 Low planetary sun gear 52 Snapring HT 740D HT 750D AUTOMATIC TRANSMISSIONS A Foldout 15 Gear unit and main shaft assembly HT 740D HT 747D exploded view 9195 FOLDOUT 15 9963 B Foldout 15 Gear unit and main shaft assembly HT 750CRD HT 754CRD exploded view Copyright 1983 General Motors Corp 1 Gear unit and main shaft assembly 2 Thrust washer 3 Front planetary sun gear 4 Thrust washer 5 Front planetary carrier assembly 6 Flange and carrier assembly 7 Sleeve bushing 8 Bronze thrust washer 12 9 Needle roller bearing 6 10 Pinion 6 11 Steel thrust washer 12 12 Pinion pin 6 13 Thrust washer 14 Internal snapping 15 Front planetary ring gear 16 Center planetary carrier assembly A 17 Pinion pin 4 18 Center p
363. ply Loctite Sleeve Retainer No 601 or equivalent to th3 outer diameter of a new bushing Install the bushing using tool J 24207 Press the bushing flush with to 0 010 inch below its adjacent surface fig 6 68 6 Using alathe with a four jaw chuck mount the carrier with surface A facing the chuck Insert the six fabricated dummy pins into the pinion pin holes Adjust the chuck centering the carrier based on surface B and the runout of the dummy pins 7 Total runout of bushing after boring must not exceed 0 002 inch Use figure 6 68 jas a guide ADJUST CHUCK JAWS TO ACHIEVE O TIR THIS LOCATES TRUE POSITION OF DUMMY PINS SURFACE B 2 7534 69 936 MM 2 2519 69 898 Mua DIAMETER A MUST BE PERPENDICULAR WITH SURFACE B WITHIN O 001 0 02 MM TIR WITH RESPECT TO SURFACE B AND THE TRUE POSITION OF THE SIX 6 DUMMY PINS DIAMETER A SHALL BE WITHIN THE TOTAL RUNOUT SPECIFIED BY 45 62 2 MM P 7 i 0 6399 15 253 MM 0 6394 16 240 Fig 6 68 Front carrier assembly bushing installation 158264 Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS 6 24 LOW SUN GEAR AND HUB HT 750DRD HT 750DRD DB Check the gear and hub assembly If the assembly is worn or damaged or has loose components replace the assembly If bushing replacement is necessary proceed as follows a If the bushing is worn replace it with a new bushing Remove the worn b
364. pply oil is provided by an engine driven pump located in the transmission housing Because the pump location is ahead of the transmission gearing and clutches the pump cannot be motored by pushing or towing the vehicle Therefore anytime that the vehicle must be towed or pushed the driveline must be disconnected or the driving wheels must be lifted off the ground 1 6 SPECIFICATIONS AND DATA The specifications and data in the chart below provide a quick reference to the major characteristics of the transmission Copyright 1983 General Motors Corp 1 8 Rating Input Input Input Idle speed in range Mounting Engine Converter housing Rear Drive Remote optional GENERAL INFORMATION SPECIFICATIONS AND DATA CHART torque net installed speed full load gov horsepower net installed dropbox Rotation view from input Input Output in forward ranges Torque converter 1300 Ib ft 1762 Nem max 1900 rpm min all models 2400 rpm max HT 740D HT 750DRD HT 754CRD 425 817 kW max 500 rpm min SAE 1 automotive flange oix hole SAE 2 mounting pad earlier models have four hole SAE 1 mounting pad Two six bolt threaded pads Flex disk otraight through converter side pads and rear housing top pad Dropbox trunion mount at front with dropbox side pads Clockwise Clockwise i oingle stage poly phase 3 element TC 470 TC 495 TC 496 TC 497 TC 498 TC 499 m
365. pring 8 and relay valve 7 NOTE Note or sketch position of adjusting ring 15 in relation to retainer pin 6 before removal 3 Depress adjusting ring 15 against its spring and remove retainer pin 6 4 Remove adjusting ring 15 washer 14 valve stop 13 spring 12 and valve 10 HT 750DRD or valve 11 HT 750CRD 754CRD b From HT 750 754CRD assemblies remove retainer pin 4 and plug valve 16 NOTE Refer to above b Assembly A foldout 21 1 Install into HT 750 754CRD assemblies plug valve 16 and retainer pin 4 NOTE Valves when installed dry should move by their own weight 2 Install valve 10 HT 750DRD or valve 11 HT 750 754CRD into valve body 3 3 Install spring 12 valve stop 13 washer 14 and adjusting ring 15 Align the hole in valve stop 13 with the pin hole in valve body 3 Position the adjusting ring in the same position as it was before removal a 3 above 4 Press inward against adjusting ring 15 until retainer pin 6 can be installed 5 Install relay valve 7 spring 8 valve stop NOTE In earlier models valve stop 9 consisted of two separate pieces 6 Press inward against valve stop 9 and install retainer pin 5 6 9 LOCKUP CUTOFF VALVE BODY ASSEMBLY a Disassembly A foldout 21 NOTE When reinstalled each valve should go into the same bore from which it was removed 1 Remove retainer pins 30 31 and 32 from valve body 29 Copyright 1983 General Motors
366. r 19 Scavenge pump tube 20 Bolt 112 13 x 3 114 B 21 Idler gear spindle 22 Snapring 2 23 Single row ball bearing 24 Bearing retainer washer 6 25 PTO idler gear 26 Rivet 3 27 Bolt 1 2 20 x 1 1 4 early models C Bolt 1 2 20 x 3 3 4 late models C 28 Lockwasher 112 29 PTO gear retainer 30 PTO gear assembly 31 Bearing retainer washer 6 32 PTO gear 33 Rivet 3 34 Single row ball bearing Torque Ib ft Nem A 26 32 35 43 B 81 97 110 131 C B3 100 113 136 1 Sealring 2 Retarder plate assembly Bolt 318 16 x 1 112 A 4 Bolt 318 16 x 1 18 A 5 Bolt 3 8 16 x 3 6 Aged with item 2 A Bolt 3 8 16 x 4 6 Used with item 19 A 6 Thrust bearing race 7 Roller bearing assembly 8 Thrust bearing race 9 Sealring 10 Retarder rotor and hub balancing assembly 11 Sealring 12 Thrust bearing race 13 Roller bearing assembly 14 Thrust bearing race 15 Retarder housing gasket 16 Retarder housing assembly 17 Flat washer 2 18 Fillister head machine screw 2 B 19 Retarder plate assembly 20 Pipe plug 1 8 5 some models C Pipe plug 1 8 4 some models C Pipe plug 1 8 1 later models Torque Ib ft Nem A 36 43 49 58 B 3 4 4 5 C 4 5 5 7 7400 HT 7500 AUTOMATIC TRANSMISSIONS A 2 IB 5 113646 12130 NY A Foldout 12 Scavenge oil pump and power takeoff driven gear exploded view B Foldout 12 Retarder hous
367. r circumference of the flex plate assembly bolts to an adapter which in turn bolts to the engine crankshaft The plate s outer circumference bolts to flywheel 12 The flywheel is bolted to torque converter pump 33 A Fioldout 10 Starter ring gear 11 al foldout is shrunk onto the flywheel Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS b Remote Drive The remote mounted transmission is driven by a shaft from the vehicle engine through universal joints to the input flange which is splined to the converter input drive housing assembly This housing assembly is bolted to the torque converter pump The direct mounted model has flex plate drive from the engine crankshaft to the transmission flywheel 2 4 TORQUE CONVERTER a Description A foldout 10 10 he torque converter consists of three elements pump assembly 36 stator assembly 13 and turbine assembly 8 These are vaned elements which are cast aluminum Pump assembly 36 is the input element and is driven by the engine through the flywheel Turbine assembly 8 is the output element and is splined to forward clutch and turbine shaft assembly 5 B Stator assembly 13 foldout 10 is the reaction torque multiplying element The stator is supported on free wheel roller race 25 which is splined to a stationary ground sleeve This stator arrangement provides an over running clutch which permits the stator to rotate freely in one direct
368. r assembly Low Planetary and Clutch Remove the low planetary carrier assembly fig 5 46 CAUTION Because the bearing fit on the carrier hub may not be tight do not attempt to carry the planetary carrier by the bearing Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS HOIST LIFFING BRACKET OUTPUT SHAFT ADAPTER REAR COVER HOUSING GASKET 52085 Fig 5 45 Removing rear cover HT 750CRD HT 754CRD PLANETARY CARRIER ASSEMBLY LOW RING GEAR CLUTCH PLATES 113 ADAPTER HOUS TG 52956 Fig 5 46 Low planetary carrier ring gear and clutch HT 750CRD HT 754CRD 2 Refer to paragraph 6 23 for rebuild of low planetary carrier assembly H Remove the low ring gear with two clutch plates fig 5 47 REAR PLANETARY CARRIER AS SEM BLY LOW UN GEA EXTERNAL CLUTCH PLATE sie Ene gem ADAPTER HOUSING MES GASKU 2208 52987 Fig 5 47 Removing low clutch plates HT 750CRD HT 754CRD 6 Remove the remaining eleven clutch plates fig 5 47 NOTE Tie the low clutch plates together and identify the pack Retain for Inspection b Remove the adapter housing and the adapter housing gasket fig 5 47 6 Refer to paragraph 6 25 for rebuild of the adapter housing assembly d First Clutch and Ring Gear 1 Remove one internal splined and one external tanged clutch plate fig 5 48 2 Remove the rin
369. r assembly TC 495 Stator assembly TC 497 Stator assembly TC 498 Stator assembly TC 499 roller thrust washer thickness front thrust washer inside diameter front thrust washer thickness rear thrust washer inside diameter Thrust bearing race thickness Roller race outside diameter OIL PUMP ASSEMBLY Body gear and cover Gear 5 end clearance between body 3 and cover 10 Body gear and cover Gear 7 end clearance between body 3 and cover 10 SCAVENGE OIL PUMP Body gear and plate Minimum depth of oil grooves 0 008 inch 0 20 mm Copyright 1983 General Motors Corp 8 2 Wear Limit in mm 0 010 0 25 0 190 4 83 0 190 4 83 0 010 0 25 0 010 0 25 0 022 0 56 4 016 102 01 0 460 11 68 4 018 102 06 0 029 0 74 3 998 101 55 0 006 0 15 0 006 0 15 Illustration A foldout 12 9 18 13 B foldout 13 20 21 22 foldout 14 B foldout 14 16 Part Number 6773624 6773625 6771151 6773624 6834679 6835687 6835605 23011235 6835687 6834679 6834319 6835748 6834487 6880727 6834488 6834720 6883005 WEAR LIMITS AND SPRING DATA Table 8 1 WEAR LIMITS cont Description SCAVENGE OIL PUMP cont Gear 11 end clearance between body 9 plate 13 Body gear and plate Gear 18 end clearance between body 9 plate 13 FORWARD CLUTCH External tanged clutch plate Thickness Cone Internal splined clutch plate thickness Fourth clutch dr
370. r balancing c Assembly 1 If the starter ring gear was removed install a new gear as follows 2 Install the starter ring gear after heating it uniformly to 4000F 2040C maximum temperature Be sure the chamfers of the teeth are facing the proper direction for starter pinion engagement The ring gear must seat firmly against the shoulder on the flywheel J 29535 2 GUIDE PLATE A CE 1 eer BASE PLATE BOLT 12 13 x 3 L 2 LOCKUP CLUTCH HUB TURBINE 17729A Fig 6 8 Rivet installation fixture Sete 4 phan BOLT 12 13x 312 RAE omg ea EN Fig 6 9 Staking converter turbine rivets 3 Place flywheel12 A foldout 9 on the assembly table with the cavity side upward 4 pu pstall_sealring A foldout 10 onto the flywheel hub and sealring 2 onto the outside diameter e EET clutch piston 3 Lubricate both sealrings 5 Place a pencil mark on the edge of the lockup clutch piston opposite a dowel pin hole Also place a pencil mark in the flywheel bore opposite a dowel pin 6 Install the lockup clutch piston into the flywheel aligning the pencil marks to engage the recesses in the piston with the dowel pins Be certain the dowel pins are engaged Copyright 1983 General Motors Corp 6 4 REBUILD OF SUBASSEMBLIES 7 Install the lock key in the lock key groove of the flywheel fig 6 2 Use oil soluble grease to retain it 8 Install the lockup clutch plate fi
371. r rocker clevis begins upward travel as in normal injection cycle forcing the master piston upward and creating a high pressure oil flow to the slave piston The ball check valve in the control valve Imprisons high pressure oil in the master slave piston system 4 The slave piston under the influence of the high pressure oil flow moves down momentarily opening the exhaust valve while the engine piston is near Its top dead center position releasing compressed cylinder air to the exhaust manifold 5 Compressed air escapes to atmosphere completing a compression braking cycle METHOD OF DRIVING A VEHICLE EQUIPPED WITH A JACOBS ENGINE BRAKE The proper method of driving a vehicle equipped with a Jacobs Engine Brake will be simple for an operator to learn Since the Engine Brake Is most effective at rated engine speeds gear selection Is very Important Gearing down the vehicle within the limits of rated engine speed makes the Engine Brake a more effective retarder Obviously maximum retarding occurs with the selection of the lowest gear that prevents exceeding rated engine speed The Engine Brake kit contains a progressive switch that provides two degrees of engine braking This switch provides the operator with greater flexibility of engine retarding After short practice drivers will learn the combination of gears that will give the best results over a particular route 2 ENGINE BRAKE INSTALLATION This manual contains instructions for Engine Brake ins
372. r splines first fig 7 12 5 Install the three remaining clutch plates as shown in figure 7 12 Be sure a thick plate is placed next to the piston refer to above PLATE 10 oru Fig 7 12 Installing first clutch plates Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS ig LIFTING SLING 31945 Fig 7 13 Installing rear cover assembly HT 740D 747D b Rear Cover Assembly 1 Place the rear cover gasket onto the rear cover Retain the gasket with oil soluble grease ig 7 13 Be sure the holes in the gasket are aligned with those in the main housing 2 Attach a lifting sling to the rear cover fig 7 13 Carefully install the rear cover assembly as assembled in para 6 26 guiding the two dowel pins into place Dowel pins are different sizes 3 Install twenty one 1 2 13 x 2 inch bolts and three 1 2 13 x 3 1 4 inch bolts and lockwashers to retain the rear cover Tighten the bolts to 67 80 Ib ft 90 108 N m 4 Install the governor assembly into the rear cover by rotating it counterclockwise fig 7 22 5 Install the governor cover and gasket Retain them with four 5 16 18 x 9 16 inch bolts Tighten the bolts 10 13 Ib ft 14 17 Nem fig 1 1 6 Invert the transmission front upward NOTE Continue assembly of Model HT 740D HT 747D at 7 6 INSTALLING FIRST CLUTCH GEAR UNIT SECOND CLUTCH CENTER SUPPORT HT 750CRD HT 754CRD a First Cl
373. r to the output us In reverse gear torque is transmitted through the fourth clutch housing sun gear shaft assembly 23 B foldout 15 center carrier assembly 16 and main shaft assembly 34 to the low sun gear and carrier NOTE In fifth gear because both the forward a n d fourth clutches are engaged all four planetaries rotate as a unit This gives direct drive through the transmission 2 18 PLANETARY GEARING HT 750DRD a Description Aj foldout 16 1 The planetary gearing in both the HT 750C 754CRD E d is similar The description in items and 3 paragraph 17a is E b by changing S ldo foldout 15 to foldout 16 and 18 B foldout 18 to 29 Aj foldout 19 The above Copyright 1983 General Motors Corp 2 10 DESCRIPTION AND OPERATION items describe the gear unit and shaft assembly and its three planetary gear sets 2 The low planetary gear set is located behind the gear unit and main shaft assembly Refer to It contains a carrier assembly a sun gear a nda ring gear The sun gear is driven by the rear planetary ring gear The 1 o w ring gear is splined to the output shaft and driven by the low planetary pinions which in turn drive the carrier and the output shaft 3 Planetary reaction of the three unit planetaries front center rear work independently of the low planetary system in all but first gear These three planetaries are required to produce second third fourth fifth and re
374. ral Operation First Gear Torque Path oecond Gear Operation Third Gear Operation Fourth Gear Operation Fifth Gear Operation Reverse Gear Operation 2 43 TORQUE PATHS THROUGH TRANSMISSION HT 750DRD DB 12 44 Paragraph Page PREVENTIVE MAINTENANCE 3 1 SCOPE 3 1 3 2 INSPECTION AND CARE 3 1 3 3 DIPSTICK CALIBRATION a Dipstick Calibration 3 1 b Six Inch Deep Oil Pan 3 1 c Seven and Eight and One Half Inch Deep Oil Pan 3 1 d Full and Add Marks 3 1 e Dropbox Models 3 1 3 4 OIL LEVEL CHECKS a Importance of Proper E27 OR b Foaming and Aerating Protect Fill Pipe d Oil Level Check Procedure e Dropbox Oil Check 3 5 HYDRAULIC FLUID RECOMMENDATIONS a Recommended Fluids 3 9 b Other Approved Fluids 3 4 c Cold Weather Start up 3 4 3 6 CHANGING THE OIL AND FILTERS a Cleanliness
375. rd and the driven gear fig 6 91 7 On models with a rear parking brake remove eight 1 2 13 bolts 11 B and NOTE lockwashers 10 and remove bearing retainer assembly Refer to paragraph 6 2 12 gasket 8 and spacer fig 6 88 T 8 On models with a rear output disconnect gt lt RETAINER ASSY assembly A foldout 23 remove six bolts 29 washers 28 adapter 27 and gasket 8 B foldout 22 Remove pie snapring 32 A foldout 23 and drive coupling 31 ern dE 6 7 E m 9 If parts replacement is necessary remove GC Y oil drain tube 14 or 32 B foldout 22 baffle 16 or 35 and oil seal 15 or 34 from bearing retainer assembly 12 or 31 10 Position a wood 2 x 2 in 50 8 x 50 8 mm board to hold the output driven gear in place 6 89 Using a soft drift drive the output shaft out through the rear opening The rear bearing and a spacer will come out with the shaft WP TRANSFER IDLER GEAR TOOL J 23544 Fig 6 88 Removing rear bearing retainer assembly TRANSFER HOUSING Fig 6 87 Removing transfer idler gear spindle 2x2 WOOD FRONT BEARING Fig 6 89 Removing rear output shaft Copyright 1983 General Motors Corp 6 58 FRONT BEARING ai p i 91107 Fig 6 90 Removing front bearing from transfer housing RANSFER HOUSING Fig 6 91 Removing transfer driven gear b Assembly NOTE Chill spindle 7 A
376. rear of the retarder rotor fig 5 33 4 Remove two screws 18 and two washers 17 B Lfoldout 12 releasing the pitot tube into oil collector ring 6 B foldout 13 Copyright 1983 General Motors Corp 5 14 Sarez es Nn E 5 Fig 5 33 Removing retarder rotor ass 53761 Fig 5 34 Removing retarder housing assembly 5 Install two 3 8 16 eyebolts into the front side of the retarder housing fig 5 34 Attach a chain or sling to the eyebolts Remove the retarder housing and front support and gasket Refer to para 6 16 for rebuild of the retarder housing and front support assembly DISASSEMBLY OF TRANSMISSION 6 Remove bearing race 2 B foldout 13 or bearing 24 A foldout 13 if they adhere to the front support hub 5 11 REMOVING FORWARD FOURTH THIRD CLUTCHES a Forward Fourth Clutches 1 If the pitot tube or steel block fig 5 34 was not removed from the oil collector ring remove it 2 Grasp the turbine shaft fig 5 35 and lift out the forward clutch and turbine shaft assembly CAUTION Do not let weight rest on the governor oil collector 3 During removal of the forward clutch assembly do not lose race 16 foldout 13 needle bearing 17 or race 18 if they adhere to the forward clutch hub 4 Refer to paragraph 6 17 for rebuild of the forward clutch and turbine shaft assembly 5 Place the hooked legs of lifting tool J 24209 under the edges of the fou
377. removing the dipstick clean around the end of the fill pipe d Oil Level Check Procedure 1 Check the oil while the vehicle is on level ground and the parking brake applied Start the engine and shift the trans Copyright 1983 General Motors Corp 3 2 PREVENTIVE MAINTENANCE mission through all drive ranges to fill the clutch cavities and oil passages then shift to neutral 2 Shift the engine for at least one minute at 1000 1200 rpm to clear the system of air CAUTION Do not overfill the transmission Overfilling can cause aeration of the oil milky appearance If overfilling occurs drain oil as required to bring it to the proper level 3 Cold Oil Check COLD RUN band Run the engine for one minute at 1000 rpm to charge the system ldle the engine until the temperature reaches 60 120 F 1649 C With the engine idling and the transmission in neutral remove the dipstick from the oil filler tube and check the oil level Oil registering in the COLD RUN band indicates a sufficient quantity of oil to safely operate the transmission until the temperature reaches 160 200 F 71 93 C When the temperature is 160 200 F 71 93 C a hot oil check must be made 4 Hot Oil Check FULL and ADD Be sure the temperature has reached 160 to 200 F 71 93 With the engine idling and the transmission in neutral remove the dipstick from the oil filler tube and check the oil level If the oil level registers between the
378. ressure below provides the automatic shifting in the transmission Refer also td 2 31b i k and below for additional information about automatic shift circuits 2 21 CONTROL VALVE ASSEMBLY a Description foldout 20 Control valve body assembly 1 includes the various valves springs and other components which control t h e selection of ranges and the automatic shifting of gears The valve body assembly is bolted to the bottom of the transmission housing which is channeled to direct the flow of oil between the valve body and clutches and other components b Operation Refer td paragraph 2 31 below for operation of the control valve body assembly 2 22 LOW SHIFT AND TRIMMER VALVES a Description A Low shift valve body assembly 2 contains a relay valve a shift valve springs pins and an adjusting ring It is mounted at the back of the control valve assembly and retained by bolt 1 Mounted directly under the low shift valve body is low trimmer valve body assembly 18 This body consists of a valve trimmer and retainer plugs a spring a valve stop and a pin Six bolts 17 extending through both valve bodies and the control valve assembly into the transmission housing retain the two bodies b Operation foldouts 6 7 and 8 With the selector valve placed in the Drive 1 D1 position hydraulic fluid is directed to the 1 2 shift signal valve foldout 6 or through the 1 2 shift signal valve to the
379. ressure is exceeded 5 On 1 HT 750CRD or HT 754CRD foldout 6 drive 1 drive 2 drive 3 drive 4 and drive 5 are forward ranges Anytime the vehicle moves forward except 2nd gear start units regardless of what range was selected it starts in first gear Shifting is automatic in any of the above ranges varying with vehicle speed and throttle position 6 On model HT 750DRD foldouts 7 and 8 drive 1 drive 2 drive 3 drive 4 and drive 5 are forward ranges Drive 1 is the only range of the five forward ranges that does not include an automatic shift The remaining four ranges 2 5 provide automatic shifts up or down according to vehicle speed and throttle position and within the gears embraced by the selected range 7 On the HT 740D HT ZAD 5 the 750CRD 754CRD f foldout 6 forward regulator pressure is directed from the selector valve to the main pressure regulator valve when the selector valve is in any position except reverse On late production HT 740 HT 747D 2nd gear start units forward regulator pressure is also directed to the top of the 1 2 modulator valve In neutral and all forward drive ranges this regulator pressure assists the pump pressure acting downward upon the main pressure regulator valve In reverse t h e forward regulator pressure is absent f r o m the main pressure regulator valve This allows the valve spring to exert its full force upward against the regulator v
380. ring 4 23 Pinion 4 24 Steel thrust washer 8 HT 750 CRD 1 HT 754 CRD HT 740D HT 750D AUTOMATIC TRANSMISSIONS 7 HT 750 CRD HT 754 CRD HT 740 D A Foldout 18 First clutch exploded view 9863A 99494 Copyright 1983 General Motors Corp B Foldout 18 Adapter housing low clutch plates and low carrier HT 750CRD HT 754CRD exploded view FOLDOUT 18 1 Adapter housing gasket 2 Adapter housing and piston assembly 3 Self locking retainer ring 4 4 Spring retainer 5 Piston release spring 28 6 First clutch piston 7 Piston inner sealring 8 Piston outer sealring 9 Adapter housing assembly 10 Adapter housing 11 Dowel pin 3 8 x 3 4 12 Dowel pin 7 16 x 3 4 13 Orifice plug 14 Internal splined clutch plate 6 15 External tanged clutch plate 7 16 Thrust race 17 Needle roller bearing 18 Thrust race 1 Bearing spacer 2 Internal snapring 3 Spring retainer 4 Piston release spring 30 5 Low piston 6 External sealring 7 Internal sealring 8 Adapter housing gasket 9 Transfer housing adapter assy 10 Transfer housing adapter 11 Oil seal 12 Pipe plug 1 8 2 B 13 Governor support pin 14 Dowel pin 15 Dowel pin 6 Breather 17 Seal plug 18 Bolt 1 2 13 x 1 3 4 21 A 19 Lockwasher 112 21 20 Lockwasher 1 2 22 21 Bolt 1 2 13 x 5 3 4 22 A 22 Bolt 1 2 13 x 7 3 4 2
381. ring race 14 flat side first onto the rear of center planetary ring gear 12 Retain it with oil soluble grease Install needle roller bearing 15 onto race 14 Retain it with oil soluble grease 5 Install thick flat bearing race 19 onto bearing 15 Retain it with oil soluble grease 6 Install rear planetary sun gear 16 into the rear of center planetary ring gear 12 Retain it with snapring 13 7 Install main shaft 11 smaller end first through the parts 12 13 14 15 16 19 assembled above Install shaft 11 and its assembled parts into drum 17 until bearing race 19 seats in the front counterbore of rear planetary carrier assembly 25 8 Install bearing race 22 flat side first onto the rear hub of rear planetary carrier assembly 25 Retain it with oil soluble grease Install bearing 21 and thick flat race 20 onto bearing 21 retaining each with oil soluble grease 9 At the rear of carrier assembly 25 install low sun g e ar 24 extended hub first over the rear end of shaft 11 Retain it with snapring 23 10 Position the assembly front upward and support the rear of carrier assembly 25 11 Install center planetary carrier assembly 10 outer splines upward into drum 17 Install front planetary ring gear 9 outer splines first into drum 17 Retain gear 9 with snapring 8 12 Install thrust washer 7 onto main shaft 11 Install sun gear and shaft assembly 6 larger diameter first onto shaft 11 13 Ins
382. roper oil filter Keep the filters in cartons until ready for installation b Change Interval The transmission oil and filters should be changed at the intervals recommended in the following Oil and Oil Filter Change Intervals Chart These intervals may vary under different operating conditions such as extreme heat and dusty conditions If the oil shows traces of contamination or the effects of high operating temperature change the oil and filter regardless of miles or hours of operation c Oil Capacity Determine the amount of oil required for an oil change from the following U S Application Quarts Liters 6 inch deep oil pan 33 31 7 inch deep oil pan 33 31 8 1 2 inch deep oil pan 37 0 35 Dropbox 2 6 2 5 CAUTION Do overfill the dropbox Overfilling can cause excessive oil temperatures If oil level is above the FULL line drain oil as required to bring it to the proper level Copyright 1983 General Motors Corp PREVENTIVE MAINTENANCE OIL AND OIL FILTER CHANGE INTERVALS Suction screen External main Oil change in oil pan pressure oil filter Coaches 100 000 miles At 500 000 miles After first 5 000 160 000 km or 804 500 km miles 8 000 km 12 months or overhaul thereafter every 25 000 miles 40 000 km or 6 months Trucks 50 000 miles At 500 000 miles After first 5 000 on highway 80 000 km or 804 500 km miles 8 000 km 12 months or overhaul thereafter every 50 000 miles or 12 months Truc
383. rough models 5 5 REMOVING REMOTE COVER FLYWHEEL AND LOCKUP CLUTCH NOTE Position the transmission front end upward a Removing Remote Front Cover B foldout 1 2 Remove the twenty two 7 16 inch bolts and lockwashers that retain cover 4 B foldout 9 to the converter housing Remove nut 1 and spacer 2 Copyright 1983 General Motors Corp 5 3 _ JACK 10 ti es Lat BEA 1 ana 5317 Fig 5 5 Removing transmission front cover 3 If necessary use jack screws to loosen cover mE 0 5 4 Lift off cover 4 and discard gasket 5 b Remove cover seal 3 for replacement only 6 If replacement is necessary remove ball bearing 6 from the shaft on drive housing 7 or from the bore in cover 4 b Removing Flywheel Lockup Clutch NOTE Position the transmission horizontally 1 Place a suitable container beneath the flywheel to catch any excess oil which may drain during removal of the flywheel 2 Remove twenty nine of the thirty bolts and washers that retain the flywheel on the converter pump fig 5 6 3 Install lifting tool J 24365 onto the flywheel fig 5 7 NOTE Guide bolts J 24315 2 shown in figures 5 7 5 8 lare used only for installing the flywheel HT 740D HT 750D AUTOMATIC TRANSMISSIONS A re CONVERTER HOUSING ic A aT Fig 5 6 Removing f
384. rough the gasket Bottom all screws before tightening them 10 Alternately tighten screws 1800 apart to 5 pound feet 7 N m Repeat the process tightening the screws to 10 13 pound feet 14 18 N m 11 On earlier models install the filler tube at the side of the pan Tighten the filler tube retainer nut to 90 100 Ib ft 122 136 N m On later models install the oil drain plug at the rear of the oil pan Tighten the plug to 15 20 Ib ft 20 27 N m 12 Remove the dipstick pour approximately 30 US quarts 28 4 liters of transmission fluid into the transmission through the filler tube Then check the oil level using the procedure described i 3 7 OIL CONTAMINATION a Examine at Oil Change At each oil change examine the oil which is drained for evidence of dirt or water A normal amount of condensation will emulsify in the oil during operation of the transmission However if there is evidence of water check the cooler heat exchanger for leakage between the water and oil areas Oil in the water side of the cooler or vehicle radiator is another sign of leakage This however may indicate leakage from the engine oil system Any accumulation of sludge or soft dirt in the sump should be removed b Metal Particles Metal particles in the oil except for the minute particles normally trapped in the oil filter indicate damage has occurred in the transmission When these particles are found in the sump the transmission
385. rs 17 as each guide screw is re moved Tighten the screws to 3 4 Ib ft 4 5 Nem Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS 8 Remove the 6 inch bolt leaving the 7 inch headless bolt in place b Rotor Components 1 Coat thrust bearing races 8 and 12 B foldout 12 with oil soluble grease and install them flat sides first onto the front and rear respectively of the hub of the retarder rotor assembly 2 Coat bearing assemblies 7 and 13 with oil soluble grease and install them onto races 8 and 12 3 Install race 6 coated with oil soluble grease onto the front support at rear of the converter housing assembly 4 Install race 14 coated with oil soluble grease onto the front hub of the retarder housing installed on transmission 5 Coat sealrings 9 and 11 with oil soluble grease and install them onto the front and rear respectively of the hub of the rotor assembly 6 Install the rotor assembly bolt heads upward toward front of transmission onto the turbine shaft splines Seat the rotor on the thrust bearing race at the rear When the rotor is seated the rotor front vanes should be approximately one inch below the front surface of the retarder housing 7 14 INSTALLING TORQUE CONVERTER HOUSING models with retarder a Housing With 2 Bolt Top Cover 1 Make sure that bearing race 6 foldout 12 and sealring 1 are in place at the rear of the converter hou
386. rst clutch is applied two is transmitted through the torque converter as described clutches must be applied to produce output shaft in a above The forward c 1u t c h is not engaged rotation in either forward or reverse Thus the torque is not transmitted beyond the fourth Copyright 1983 General Motors Corp 2 24 DESCRIPTION AND OPERATION LOCKUP TORQUE Pp 7 THIRD CLUTCH CONVERTER A CLUTCH y TURBINE i SHAFT MAIN SHAFT SUA GEARS SHAFT CONNECTING FRONT PLANET AR i 4 CENTER PLANETARY FOURTH SECOND i CLUTCH CLUTCH nei t iugum FIRST CLUTCH SHAFT REAR SUN GEAR X REAR PLANETARY IM ES CLUTCH APPLIED DRUM md TORQUE PATH Fig 2 3 First gear torque path HT 740D HT 747D d First Gear Operation fig 2 3 Engine torque is transmitted through the torque converter as described in a above The forward and first clutches are applied The first clutch application anchors the rear planetary ring gear against rotation The forward clutch application locks the turbine shaft and transmission main shaft together so that they rotate as a unit The rear sun gear is splined to the m a i n shaft and rotates with it and in turn it rotates the rear planetary pinions The pinions are part of the carrier assembly which is splined to the transmission output shaft With the rear ring gear held stationary by the app
387. rst gear is omitted 2 With an increase in output speed the governor will transmit a higher pressure to the lockup valve Copyright 1983 General Motors Corp 2 18 DESCRIPTION AND OPERATION 3 When the pressure is sufficient the lockup valve moves downward compressing its spring This opens a path for pressure to flow to the lockup clutch piston Lockup is now engaged Main pressure applies the lockup clutch in models not equipped with lockup cutoff valves When lockup cutoff valves are included clutch apply pressure from the drive clutch engaged is used to apply the lockup clutch m Priority Valve 1 The priority valve insures that the control system upstream from the valve will retain sufficient pressure during shifts to perform its automatic functions 2 Without the priority valve the filling of a clutch might require a greater volume of oil momentarily than the pump could supply and still maintain the necessary control pressures n Clutch Circuits Drive Ranges HT 740D HT 747D foldout 5 5 1 There are five clutches in the transmission These are first clutch second clutch third clutch fourth clutch and forward clutch The clutches are applied for various conditions as follows Condition Clutch es applied Neutral First First gear First and forward Second gear Second and forward Third gear Third and forward Fourth gear Fourth and forward Reverse First and fourth 2 Each of the five clutches
388. rth clutch assembly cross section view NN 94350 CLUTCH PLATES FOURTH CLUTCH A Tx EM 2 AIEO ATE PH E A CK Er ud aif Fig 6 52 Checking fourth clutch clearance 11 If a press is not available the piston may be installed with a mallet Tap the piston lightly in a continuous circular pattern until the piston is properly seated Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS 12 Install twenty piston release springs one each on the twenty cast bosses on the fourth clutch piston fig 6 48 13 Install the spring retainer recessed side outer lip down on the twenty piston return springs 48 14 Compress t h e spring retainer using J 24204 2 and J 24204 3 tools until the snapring groove on t h e clutch hub is clear fig 6 49 Install the snapring WARNING Do not install forward clutch h u b 19 B foldout 13 a n d fourth clutch driving hub 22 into the fourth clutch housing assembly 12 AJ foldout 14 If these two hubs are installed into the fourth clutch housing assembly by mistake the transmission will operate in reverse when the driver selects any forward range 15 Grease with oil soluble grease and install the bearing race onto the rear hub of the fourth clutch housing fig 6 47 16 Grease with oil soluble grease and install the bearing race onto the front hub of the fourth clutch housing assembly fig 6 46 6
389. rth clutch spring retainer and remove the fourth clutch fig 5 36 NOTE Keep both front and rear bearing races with the clutch assembly during rebuild 6 Refer to paragraph 6 18 for rebuild of the fourth clutch assembly b Third Clutch 1 Remove the snapring fig 5 36 that retains the third clutch backplate Remove the backplate Copyright 1983 General Motors Corp 9 15 HT 740D HT 750D AUTOMATIC TRANSMISSIONS avi E TURBINE SHAFT 6 FORWARD CLUTCH ful ASSEMBLY GOVERNOR OIL COLLECTOR THANSMISSION RING HOUSING S9 ocean on 53760 Fig 5 35 Removing forward clutch assembly ODORE INC ODDO CEU cue y X ri E FOURTH CLUTCH P c xu g r e os ONE LL Ae BEARING eres y ILES o 89 M Fig 5 36 Removing fourth clutch assembly 2 Remove eight third clutch plates NOTE Tie the third clutch plates together and identify the pack Retain for Inspection 5 12 REMOVING CENTER SUPPORT GEAR UNIT SECOND CLUTCH HT 740D 747D or HT 750DRD a Center Support 1 Remove the center support anchor bolt and washer fig 5 37 2 Remove the snapring that retains the center support assembly fig 5 38 3 Install c e n t e r support lifting bracket J 24195 into the recess between the sealrings on the center support hub fig 5 39 CAUTION The center support is fitted to the transmission housing with
390. rvice outlets See your yellow pages under Engines Diesel or Transmissions Truck Tractor etc TABLE OF CONTENTS Paragraph Page Section 1 General Information 1 1 SCOPE OF MANUAL a Coverage 1 1 b Illustrations esee 1 1 c Maintenance Information 1 1 1 2 SUPPLEMENTARY INFORMATION 1 1 1 3 ORDERING PARTS a Transmission Nameplate 1 1 b Parts 1 4 GENERAL DESCRIPTION Automatic Shifting Torque Converter LOCKUP Clutch sueesssse Hydraulic Retarder Power Takeoff Provisions Planetary Gearing GUCE S 1 6 g Control Valve Body Assembly essere 1 6 h Output Transfer Housing ONO DO OX d e T 1 7 i Output Disconnects 1 7 9oceocgp 1 5 OPERATING INSTRUCTIONS Vehicle Related Controls Neutral m Forward Drive Ranges HOVOLISO Range Selection Hydraulic Retarder TONINO er 9ococp Q 1 6 SPECIFIC
391. s of the splines should slide over the snapring until the snapring engages and expands into the groove in the PTO gear 9 Before completing the assembly the clutch clearance must be established One method is direct measurement as outlined in 10 through 13 below An alternate method is by stack dimension computation outlined If the stack method is used disregard 10 through 15 below NOTE If the forward clutch housing is replaced selection of a proper piston A B or C is imperative before sealring installation If the forward clutch housing is CHECK CLEARANCE HERE 0080 0 120 INCH 203 3 05 mm 94360 Fig 6 43 Forward clutch assembly cross section not replaced and a new piston is required make sure the identification letter stamped on the new piston is identical to that on the old piston 10 Using figure 6 43 las a guide install forward piston A into clutch housing 11 Beginning with an external tanged plate alternately install five external tanged plates B and five internal splined plates C into forward clutch housing 12 Install the fourth clutch driving hub D into housing E and retain it with snapring F 13 While holding hub D firmly against snapring F measure the clutch clearance with gage J 24192 at the location shown in figure 6 43 When clearance is satisfactory the thinner step of the gage will enter between the driving hub and clutch plates the thic
392. s short tons 1 102 Celsius C temperature PIN 060754 000 This fine document Was brought to you by me Liberated Manuals free army and government manuals Why do I do it I am tired of sleazy CD ROM sellers who take publicly available information slap watermarks and other junk on it and sell it Those masters of search engine manipulation make sure that their sites that sell free information come up first in search engines They did not create it They did not even scan it Why should they get your money Why are not letting you give those free manuals to your friends I am setting this document FREE This document was made by the US Government and is NOT protected by Copyright Feel free to share republish sell and so on I am not asking you for donations fees or handouts If you can please provide a link to liberatedmanuals com so that free manuals come up first in search engines lt A HREF http www liberatedmanuals com gt Free Military and Government Manuals lt A gt Sincerely Igor Chudov http igor chudov com
393. s the sun gear shaft assembly with the front sun gear splined to it at input speed The first clutch is applied also and anchors the rear ring gear against rotation The center sun gear rotates the center carrier pinions which in turn rotate the center ring gear in an opposite direction The center carrier is splined to the planetary connecting drum which is splined to the rear carrier The reverse direction of rotation of the center ring gear rotates the rear sun gear This causes the rear planetary pinions to drive the rear carrier in a reverse direction within the stationary ring gear Thus the transmission output shaft being splined to the rear carrier rotates in a reverse direction at a speed reduction shown in Copyright 1983 General Motors Corp 2 29 HT 740D HT 750D AUTOMATIC TRANSMISSIONS LOCKUP CLUTCH TORQUE CONVERTER THIRD CLUTCH S EL FORWARD LEM emus CLUTCH FORWARD CLUTCH PISTON FOURTH CLUTCH PISTON THIRD CLUTCH PISTON FOURTH CLUTCH SECOND CLUTCH FIRST CLUTCH Sud IL HO 10598 OUTPUT SHAFT zx por T m j bn TEOS IcoS aH d FIRST CLUTCH PISTON E E REAR PLANETARY CARRIER e CENTER PLANETARY CARRIER FRONT PLANETARY CARRIER SECOND CLUTCH PISTON Ez CLUTCH APPLIED H TORQUE PATH 52962 Fig 2 8 Neutral torque path HT 750CRD HT 754CRD 2 33 TORQUE PATHS THROUGH TRANS
394. se Engine HT 7500RD 5 V Conventional Diese Engine 7500RD No Lockup L NP T Conventional Diesel Engine HT 750CRD AM AE AK Conventional Diesel Engine HT 750CRD 3 69 Gear Ratio AP AQ AR Conventional Diesel Engine HT 754CRD 3 69 Gear Ratio 2nd Gear Start Copyright 1983 General Motors Corp 3 10 PREVENTIVE MAINTENANCE 2 The Kent Moore Valve and Governor Test Stand J 25000 is designed to check five principle transmission functions It performs a checking procedure on the governor modulator hold regulator shift points up down inhibit and a trimmer regulator check f a test stand is not available satisfactory calibration of shift points may be made after road testing of the vehicle b Location of Adjusting Components 1 Shift speeds are changed by changing the positions of adjusting rings that determine the retaining force of certain valve springs in the valve body Refer to items 22 74 84 93 98 and 104 B foidout 18 and 15 A foldout 20 2 A special tool J 24314 is used to depress and rotate the adjusting rings to the proper positions Clockwise rotation increases spring force and will raise the shift point Counterclockwise rotation will reduce spring force and lower the shift point NOTE Each notch of adjustment will alter the shift point as follows HT 754CRD HT 750CRD amp DRD Shift 1 2 10 rpm Shift 2 3 10 rpm Shift 3 4 25 rpm Shift 4 5 35 rpm H
395. seal 34 Internal snapping 35 Ball bearing 36 Bolt 1 2 13 x 7 1 4 3 HT 750 B Bolt 1 2 13 x 3 1 4 3 HT 740 B 3 Lockwasher 1 2 3 38 Governor assembly 71 Priority valve stop 72 Priority valve spring 73 Priority valve 74 Hold regulator valve 75 Hold regulator valve spring 76 Hold regulator valve stop 77 Washer 78 Spring adjusting ring 79 Retainer pin 80 Manual selector valve 81 Manual selector valve Before SN 10300 HT 750 82 Retainer pin 83 1 2 shift valve assist spring HT 740 2nd gear start late production units 84 1 2 shift valve HT 740 2nd gear start late production units 85 1 2 modulator valve HT 740 2nd gear start late production units 86 1 2 shift valve spring HT 740 2nd gear start late production units 87 1 2 shift valve stop HT 740 2nd gear start late production units 88 Spring adjusting ring HT 740 2nd gear start late production units 88 1 2 shift valve spring HT 740 2nd gear start early production units 90 1 2 shift valve HT 740 2nd gear start early production units 91 Signal plug HT 740 2nd gear start early production units 92 1 2 shift signal plug HT 740 2nd gear start early production units 93 1 2 2 3 shift valve 94 1 2 2 3 modulator valve 39 Governor pin and gasket assembly 40 Governor pin 2 41 Gasket 42 Governor cover 43 Bolt 5 16 18 x 9 16 4 D
396. select the second clutch components disregard 5 below 2 Invert the transmission housing rear upward 3 Remove the six bolts and washers that temporarily retained the rear cover to the transmission housing Remove the rear cover and gasket 4 Remove the thirteen first clutch plates from the transmission housing Since these plates have been preset for clearance they should be retained in a pack to prevent intermixing with other plates b Using gage J 24194 check the second clutch plate clearance Hp 77 The prescribed clearance is 0 095 to 0 145 inch 2 41 to 3 68 mm Any dimension within 0 095 to 0 145 inch is satisfactory However the closer the clearance is to 0 095 inch the longer the interval between clutch plate replacements will be Replace worn plates with new plates to establish the desired clearance Recheck the clearance as described above NOTE Leave the second clutch and the center support in the transmission housing until the housing is again positioned front upward Continue assembly of Model HT 740D HT 747D at paragraph 7 5 das CLUTCH PLATES 33 r Lm i uw ed jd f m A P Y p i v ys d CL e gt r y CENTER 5U P708 E EG f Pu n 1 i 1 iN 2304 y Fig 7 7 Checking second clutch plate clearance 7 4 ESTABLISHING CLUTCH CLEARANCES SELECTING CENTER SUPPORT SNAPRING HT 750CRD HT 754CRD HT 750DRD HT 750DRD D
397. selector lever into R reverse position With forward regulated pressure absent the 1 2 shift spring at the top of the 1 2 shift valve will force the 1 2 modulator and 1 2 shift valves to the bottom of their bores This blocks main pressure flow to the top of the 1 2 relay valve leaving the valve at the top of its bore and permits reverse pressure from the selector valve to pass through the bottom of the 1 2 relay valve to the fourth and first clutches Reverse pressure is also directed through the trim regulator valve to the trim boost area of the first second and third trimmers blocking all trimming action 2 25 OIL PAN AND OIL FILTER a Description 1 There are three different oil pans designed f o r the transmission T w o steel pans and one iron pan The steel pans illustrated in foldouts B 16 and A 17 are made of pressed steel The pan illustrated in B 16 is six inches deep measured from the splitline to the bottom of the pan The pan illustrated in A 17 is seven i n c h e s deep measured from the transmission splitline to the bottom of the pan 2 The third pan is made of cast iron It is eight and one half inches deep measured from the transmission splitline to the bottom of the pan reference BJ foldout 17 Copyright 1983 General Motors Corp 2 13 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 3 The pan holds the oil that activates the clutches valves etc and is sometimes referred to as the sump It
398. sher 8 20 Pinion 4 21 Needle roller bearing 8 22 Steel thrust washer 8 23 Center sun gear and shaft assembly 24 Split sleeve bushing 25 Center sun gear shaft 26 Split sleeve bushing 2 Thrust washer 28 Planetary connecting drum 29 External snapping 30 Center planetary ring gear 31 Thrust race 32 Needle roller bearing 33 Thrust race 34 Main shaft assembly 35 Orifice plug 36 Main shaft 3 Rear planetary sun gear 38 External snapping 39 Rear planetary carrier assembly 40 Rear planetary carrier 41 Pinion pin 4 42 Bronze thrust washer 8 43 Needle roller bearing 8 44 Pinion 4 45 Steel thrust washer 8 46 Internal snapping 47 Ball bearing 1 Gear unit and main shaft assembly 2 Thrust washer 3 Front planetary sun gear 4 Thrust washer 5 Front planetary carrier assembly 6 Flange and carrier assembly 7 Sleeve bushing 8 Bronze thrust washer 12 9 Needle roller bearing 6 10 Pinion 6 11 Steel thrust washer 12 12 Pinion pin 6 13 Thrust washer 14 Internal snapping 15 Front planetary ring gear 16 Center planetary carrier assembly 17 Pinion pin 4 18 Center planetary carrier 19 Bronze thrust washer 8 20 Pinion 4 21 Needle roller bearing 8 22 Steel thrust washer 8 23 Center sun gear and shaft assembly 24 Split sleeve bushing 25 Center sun gear shaft 26 S
399. shings for scores burs roundness sharp edges and evidence of overheating Remove scores with crocus cloth Remove burs and sharp edges with a scraper or knife blade If bushing is out of round deeply scored or excessively worn replace it using the proper size replacer CAUTION W h e n a defective bushing is removed care should be exercised to prevent damage to the bushing bore Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS TRIMMER EXHAUST THIR LUBRICATION EXHAUST FIRST SECOND FOURTH D AND FOURTH MODULATOR y p i A PIE E Lf yf mea UY 2 E ele ore MESE TRA pi M EXHAUST a EE i FORWARD REGULATOR GOVERNOR FEED Case f A ef SECOND E gt NN y M A GOVERNOR MAIN REVERSE GOVERNOR LOW SIGNAL FORWARD REGULATOR ii LO REVERSE DRIVE 1 17350 Fig 4 7 Main housing valve body mounting surface tracks 2 Inspect thrust washers for distortion scores burs and wear Replace the thrust washer if it is defective or worn h Inspecting Sealrings Gaskets 1 Inspect piston sealrings and liptype seals for nicks cuts tears splits and pattern damage Damage on old seal can indicate rough or sharp edges in piston grooves or on mating surface that could also damage new seal 2 3 Inspect hook type sealrings for wear broken h
400. shown in wiring schematic below NOTE The switch contacts are protected against arc mg by a small diode connected between the load side switch terminal and ground The Engine Brake must be connected to the load side terminal If the vehicle has a positive ground electrical system reverse the position of the diode NOTE If Engine Brake installations are to be completed on vehicles containing the following transmissions Allison Hydraulic VH Allison Off Highway Allison Super V Dana Spicer 184 Allison Electric VH the wiring circuit must be modified For complete information consult your nearest Jacobs distributor or contact the factory Service Department FROM KEY ee TERMINAL FOR NEGATIVE GROUND D ENLARGED VIEW OF DIODE Connect to WIRING DIAGRAM Diode side FOR of Buffer ENGINE BRAKES ON Switch VARIOUS ENGINE MODELS 6 71 6V 718 8V 718 6V 92 BV 92 INITIAL STARTING AND TESTING OF ENGINE BRAKE Do not operate the solenoids manually Depressing the solenoid armature will energize the Engine Brake when the Engine is being fueled Damage may result during manual operation Start engine and check lube oil pressure After engine has warmed up throw dash switch to ON position Manually open throttle to full fuel position and release instantly to permit throttle and governor to return engine to Idle speed This action will permit the governor to close the buffer switch and energize the Eng
401. side detent lever assembly 36 Locknut 3 8 F 3 Valve spacer 38 Bolt 5 16 18 x 3 4 F 39 Modulator retainer 40 Shaft retainer pin 41 Plug washer 42 Plug 3 4 16 B 43 Shaft seal assembly 44 Manual selector shaft and nut assembly C 24 Oil pan gasket 25 Pipe plug 1 8 B 26 Heater orifice plug 1 inch 2 Oil pan drain washer 28 Oil pan drain plug 29 Oil pan 8 1 2 inch depth 30 Bolt 5 16 18 x 4 3 4 23 31 Inside detent lever assembly 32 Lock nut 3 8 33 Valve spacer 34 Bolt 5 16 18 x 3 4 F 35 Modulator retainer 36 Shaft retainer pin 3 Washer 38 Plug 3 4 16 C 39 Manual selector oil seal 40 Manual selector shaft c nut assembly 41 Manual selector shaft 42 Manual selector shaft nut metrie3 43 Plug 1 8 inch 44 Nut 1 2 20 32 C 45 Lockwasher 3 46 PTO cover gasket 45 Manual selector shaft 46 Manual selector nut 47 Plug 1 8 48 Hex nut 1 2 20 3 A 49 Lockwasher 1 2 3 50 PTO cover gasket 51 PTO cover 52 Washer 3 8 6 53 Bolt 3 8 16 x 3 4 6 C 54 Lockwasher 1 2 8 retarder models 55 Bolt 1 2 13 x 6 8 retarder models A Torque Ib ft Nem A 67 80 91 108 B 4 5 5 7 C 15 20 20 27 D 9 11 2 5 E 17 20 23 27 F 10 13 14 18 47 PTO cover 48 Washer 6 49 Bolt 3 8 16 x 3 4 6 50 Lockwasher 1 2 8 51 Bolt 1 2 13x 6 8 A 52 Bolt 1 2 13x 2 11 G 53 Lockwasher 11
402. sing assembly as rebuilt in paragraph 6 2 Using a hoist lower the converter housing onto the retarder housing engaging the 1 2 x 7 inch headless guide bolt projecting from the retarder housing The three studs engage holes in the retarder housing it x af E NOTUM Fig 7 43 Installing retarder rotor assembly 3 Install seven 1 2 13 x 6 inch bolts with lockwashers into the holes inside the front of the converter housing remove 1 2 13 x 7 inch headless guide bolt to install the last bolt 4 Tighten the seven bolts to 67 80 Ib ft 90 108 Nem 5 Install eight 1 2 13 x 6 inch bolts with lockwashers through the front flange of the transmission housing the retarder housing and into the rear of the converter housing 6 Install three 1 2 inch lockwashers and three 1 2 20 nuts onto the studs projecting through the transmission housing front flange 7 Tighten the eight bolts to 67 80 Ib ft 90 108 Nem Tighten the three nuts to 67 80 Ib ft 91 109 Nem b Housing With 8 Bolt Top Cover 1 Make sure that bearing race 6 foldout 12 and sealring 1 are in place at the Copyright 1983 General Motors Corp 7 24 ASSEMBLY OF TRANSMISSION rear of the converter housing assembly as rebuilt in oaraagraph 6 12 2 Using a hoist lower the converter housing onto the retarder housing engaging the 1 2 x 7 inch headless guide bolt projecting from the retarder fig 7 44 hous
403. smission Service Indianapolis Operations 317 242 3547 or Sales Manager Indianapolis Operations 317 242 3584 When contacting the Regional or Home Office please keep in mind that ultimately your problem will likely be resolved at the distributorship or dealership utilizing their facilities equipment and personnel Therefore it is suggested that you follow the above steps in sequence when experiencing a problem Your purchase of a Detroit Diesel Allison product is greatly appreciated and it is our sincere desire to assure complete satisfaction 9 2 SERVICE LITERATURE Additional service literature is available for the owner who takes pride in his equipment These books provide fully illustrated instructions for the maintenance service overhaul and parts support of your transmission To ensure that you get maximum performance and service life from your unit see your dealer or distributor for the following publications Check the Yellow Pages under Transmissions Truck or Engines Diesel for your nearest authorized service outlet Copyright 1983 General Motors Corp OWNER ASSISTANCE AND SERVICE LITERATURE HT 700D Transmission Publications HT 700 Drivers Handbook SA 1334 HT 700 Series Parts Catalog SA 1268 HT 700 Mechanics Tips SA 1366 HT 700 Preventive Maintenance SA 1772 Copyright 1983 General Motors Corp 9 3 9 4 3 OG gt Gh m Starter ring gear Loekup clutch Torque converter turbine Torque con
404. smissions Copyright 1983 General Motors Corp 2 5 HT 740D HT 750D AUTOMATIC TRANSMISSIONS with first second third or fourth clutches it produces second third fourth or fifth gears in that sequence b Description 1 Ihe forward clutch in models HT 740D HT 747D HT 750CRD HT 754CRD HT 750DRD contain the same basic parts Each model has a clutch housing with turbine shaft attached ten clutch plates a piston a forward clutch hub and a fourth clutch driving hub 2 The clutch housing contains an oil collector ring attached to its outer diameter and works in conjunction with a pitot tube to produce front governor pressure If front governor pressure is not required a rectangular steel block is used in place of the pitot tube The clutch housing contains the forward clutch piston positioned inside the housing in its bore retained by twenty springs a spring retainer and a snapring 3 Five of the clutch plates are internal splined while the remaining five are external tanged The internal splined plates are splined to the forward clutch hub The external tanged plates are anchored against rotation to the internal grooves of the forward clutch housing c Operation B foldout 13 1 Clutch housing and shaft assembly 5 rotate when the converter turbine rotates Fourth clutch driving hub 22 also rotates causing the internal splined plates of the fourth clutch pack to rotate 2 When hydraulic pressure is direc
405. specific internal clutch plates Fig 6 109 Stack dimension for first clutch HT 740 designed for the unit are being used in this stacking or low clutch HT 750 1 Stack the first clutch plates as shown in procedure Refer to Parts Catalog Copyright 1983 General Motors Corp 6 67 HT 740D HT 750D SERIES TRANSMISSIONS 2 dimension X 980 1020 LB LOAD 30634 308314 o O Fig 6 110 First clutch stack dimension HT 750 980 1020 LB LOAD 6836418 1 X 6834720 2 USE PLATE FOR SPECIFIC MODEL 6 6834488 5 DIM X PLATE PLATE FROM 6834488 6834720 3 1950 3 1817 ADD 2 REMOVE 2 31644 31364 Fig 6 111 Second clutch stack dimension Apply the specified load and measure 3 From the table in figure 6 110 select the recommended clutch plates to satisfy the required clutch plate clearance f Second and Third Clutches 1 Stack the second clutch plates as shown n fae 6 117 Be sure the specific internal clutch plates designed for the unit are being used in this stacking procedure Refer to Parts Catalog 2 dimension X 3 From the table in figure 6 111 select the recommended clutch plates to satisfy the required clutch plate clearance Apply the specified load and measure 4 Repeat the proceduresin 1 2 and 3 above stacking the third clutch plates and piston using table in figure 6 112 980 1020 LB X LOAD 6836418 1 6834720
406. ssembly fig 6 11 Be sure the holes in the baseplate are under the rivet heads Place top plate J 29121 4 on top of the stator assembly 4 Install the 5 8 11 X 3 25 inch bolt to hold the two plates together Tighten the bolt to 60 Ib ft 81 N m 5b Place fixture stand J 25587 1 on a hydraulic press fig 6 11 Install rivet remover pin J 29121 3 into fixture J 25587 1 head Tighten the tool retainer thumb screw STATOR RIVET 10 STATOR ASSEMBEY 54305 Fig 6 10 Drilling stator rivets Copyright 1983 General Motors Corp HT 740D HT 750D SERIES TRANSMISSIONS 3 25587 1 J 29121 3 29121 4 BOLT 5 8 11X3 25 STATOR y ASSEMBLY T teen salz Fig 6 11 Removing stator rivets 6 Place the stator assembly with base and top plates onto the fixture stands drilled rivet side up 7 Align the rivet remover pin with the drilled rivet and press the rivet from the stator assembly Repeat the above process for each rivet 8 Remove the retaining bolt and top plate fig 6 11 Separate thrust washer 14 al foldout 10 side plate washer 18 two cam washers 15 and cam 17 from stator 16 9 Inspect the stator and cam for cracks rivet holes for burrs or swelling Deburr as required If cam or stator is cracked or distorted replace the stator assembly 10 If the cam becomes separated from the stator it can be reinstalled in the following manner Place the stator ona cR ta
407. st into bore J fig 6 20 of valve body 30 B foldoutl 20 14 Align the pin hole in valve stop 101 with the pin holes in the valve body Compress the spring and install retainer pin 103 into the valve body to retain adjusting Copyright 1983 General Motors Corp 6 12 REBUILD OF SUBASSEMBLIES Section H H Assan Tit 99 14 Section B B A n iY Kerap 7 T AREE m lt A he WA 171017 Ai ut AAA E BLA A DY 2 WAP Sp AY wp oy PYA oes US 2 Aes af Section F F Gag Aj laj La A E GaGa 54 20 A Y ING Gas TM 2 LA A i 7 D EET OSS 4 2 DA UA Section G G Section C C BN L UG aa LL IVa 1622 uA PA VE ZA MMA y alae AR WA eS REN VLA Section A A Section E E 9477F Fig 6 20 Control valve assembly with components installed ring 102 Be sure the adjusting ring is in the same position as it was before removal NOTE A configuration difference between the early and late production 1 2 shift valves was introduced into the transmission The early production version installed in steps 15 and 16 is 89 th ru 92 The stalled in steps 17 and 18 is 83 thru 88 Steps 19 and 20 explain the installation of the 1 2 shift valve parts used in mo
408. stalling flywheel onto the converter pump pump Engage turbine splines with the forward clutch shaft splines fig 7 60 HT 740D HT 750D AUTOMATIC TRANSMISSIONS 21 24310 Jc RETARDER HOUSING PTO GEAR VENE T Um CONVERTER HOUSING LoL RETARDER VALVE Fig 7 61 Installing flywheel retaining bolts 3 Release the hoist and remove the lifting bracket 4 Install the remaining 29 bolts and flat washers fig 7 61 Prior to Installing the last bolt and washer remove guide screw J 24315 2 5 Tighten the bolts to 41 49 Ib ft 56 66 Nem c lransmission Front Cover B foldout 9 Remote Mounting NOTE Bearing 6 B foldout 9 with only one side shielded should be replaced with a sealed bearing Refer to current Parts Catalog SA 1268 If the bearing with only one side shielded is not replaced fill the cavity in the front cover between the outside seal and bearing 6 half full of high temperature grease 1 If bearing 6 Lfoldout 9 was removed from converter drive housing 7 install a new sealed bearing Seat the bearing against the hub shoulder 2 Using the access hole at the top of the converter housing install one 3 8 24 x 1 1 4 inch b o t and one 3 8 flat washer through the converter housing into the flywheel assembly fig 7 61 Copyright 1983 General Motors Corp 7 32 ASSEMBLY OF TRANSMISSION TRANSMISSION FRONT ER BOLT GUIDE BOLT T GASK
409. ston HT 750 754 First clutch piston HT 740 747 5 Piston outer sealring 6 Piston inner sealring 7 Rear cover gasket 8 Rear cover assembly 9 Plug 1 8 NPTF A 10 Plug 1 8 NPTF A 11 Governor support pin 12 Dowel pin 3 8 x 3 4 13 Dowel pin 7 16 x 3 4 1 Control valve assembly 2 Lubrication valve 3 Check valve spring 4 Spring cup washer 5 Spring pin 6 Check valve pin 7 Oil transfer plate 8 Ball 1 4 die 9 Ball 5 16 die 10 Ball 1 4 die 11 Ball 1 4 die 12 Ball 1 4 die 13 Ball 1 4 die 14 Ball 1 4 die 15 Ball 1 4 die 16 Ball 1 4 die 17 Bolt 1 4 20 x 2 1 2 3 A 18 Modulator valve 19 Modulator valve spring 20 Retainer washer 21 Valve stop 22 Spring adjusting ring 23 Modulator actuator valve 24 Modulator valve 25 Spring 26 Adjusting ring 2 Retainer pin 28 Modulator pressure valve body 29 Separator plate 30 Control valve body 31 Third clutch trimmer valve 32 Trimmer plug 33 Trimmer valve secondary spring 34 Trimmer valve primary spring 35 Third clutch trimmer valve stop 14 Rear cover 15 Speedometer driven gear bushing 16 Lockwasher 1 2 21 17 Bolt 1 2 13 x 5 3 4 21 HT 750 B Bolt 1 2 13 x 2 21 HT 740 B 18 Internal snapping use before SN 5660 19 Output shaft assembly HT 740D HT 750CRD 20 Orifice plug 21 Output shaft and bushing assembly 22 Bushi
410. t 130 to 156 Nem Copyright 1983 General Motors Corp 6 63 HT 740D HT 750D SERIES TRANSMISSIONS 5 Install flex disk assembly 2 onto the engine crankshaft Refer to the vehicle service manual for bolt torque value 6 31 GOVERNOR a Disassembly 1 The governor may be disassembled for cleaning and inspection Do not disassemble the governor unless the kit consisting of two governor weight pins and the cover gasket is available 2 Follow t h e directions furnished with the kit to disassemble the governor NOTE Refer to above b Assembly 1 Assemble the governor as outlined in the directions furnished with the governor service kit 2 Check the governor port openings as outlined in the kit instructions Refer ta figure 6 100 6 32 OUTPUT MANUAL DISCONNECT ASSEMBLIES NOTE Upper rear lower rear or front disconnect clutch assemblies are identical The following instructions for rebuild of the upper rear assembly apply to all locations of the disconnect clutch a Disassembly Aj foldout 23 1 Remove the bolts and lockwashers which hold the bearing retainer fig 6 101 Remove the retainer and gasket but do not remove the oil seal unless replacement is necessary GOVERNOR FEED MUST OPEN 0 020 0 51 mm MIN GOVERNOR PRESSURE EXHAUST PORTS PORTS MUST OPEN 0 020 0 51 mm MIN 7849H Fig 6 100 Governor assembly showing port openings BEARING RETAINER SHIFTER SHAFT
411. t bolt Tighten the bolt to 39 46 Ib ft 53 62 Mm figure 7 12 INSTALLING TORQUE CONVERTER HOUSING models without retarder a Housing With 2 Bolt Top Cover 1 Place the converter housing assembly as assembled in para 6 10 on the work table so that both the front and rear are accessible Copyright 1983 General Motors Corp HT 740D HT 750D AUTOMATIC TRANSMISSIONS TURBINE SHAFT FORWARD CLUTCH ASSEMBLY gia RE MTOM UE GOVERNOR OIL COLLECTOR emma X TRANSMISSION RING i HOUSING a em i gt ANCHOR 1 IT Ti b me PTO GEAR E 52973 Fig 7 37 Center support anchor bolt 2 Make sure the thrust race and the needle bearing have been installed at the rear of the converter housing Refer to figure 6 22 53760 Fig 7 35 Installing forward clutch assembl lf assembly includes front pitot 5 j blocker 27 foldout 13 be installed now Tighten the screws to 30 48 in Ib 3 4 5 4 Nem 39 If installed disregard items 5 and 8 below CONVERTER GROUND LIFTING SLING CAUTION cun 5 CONVERTER HOUSINE Improper installation of the two butt AE g joint sealrings onto the front support hub may cause transmission failure 8589 1 Refer to paragraph 4 6g for proper CM installation procedure Tubi 3 Install the butt joint sealrings onto the fe 5 front support hub Attach a lifting sling
412. t Forward and first 3 69 1 3 69 1 Second Forward and second 2 07 1 2 02 1 Third Forward and third 1 40 1 1 38 1 Fourth Forward and fourth 1 00 1 1 00 1 Heverse Fourth and first 5 73 1 6 04 1 HT 750CRD Neutral Low HT 754CRD First Forward and low 3 19 1 3 19 1 3 69 1 Second Forward and first 1 8911 1 89 1 2 00 1 Third Forward and second 1 55 1 1 53 1 1 58 1 Fourth Forward and third 1 241 1 23 1 t2517 Fifth Forward and fourth 1 00 1 1 00 1 1 00 1 Heverse Fourth and low 7 9771 8 33 1 9 65 1 754CRD Neutral LOW Optional First Forward and low 3 69 1 Hatios with Second Forward and first 2 00 1 2nd gear Third Forward and second 1 5811 start Fourth Forward and third 1 25 1 Fifth Forward and fourth 1 00 1 Heverse Fourth and low 2 96 1 HI 750DRD Neutral First First Forward and low 7 97 1 7 97 1 Forward and first 3 19 1 3 19 1 Third Forward and second 2 07 1 2 02 1 Fourth Forward and third 1 40 1 1 38 1 Fifth Forward and fourth 1 00 1 1 00 1 Heverse Fourth and first 4 47 1 4 72 1 HT 750DRD DBNeutral First First Forward and low 7 97 1 Second Forward and first 3 19 1 Third Forward and second 2 02 1 Fourth Forward and third 1 38 1 Fifth Forward and fourth 1 00 1 Heverse Fourth and first 4 72 1 Dropbox only 1 00 1 Overall torque multiplication ratio of transmission output stalled is the product of the converter torque multiplication ratio and the mechanical rear ratio Only these ratios are used on HT 754CRD models
413. t needle bearing installer used with J 8092 Planetary rebuilding set Shift lever seal installer Shift lever seal remover Converter pump snapring remover amp installer PTO gear removing fixture set Inner ring driver Outer ring support Puller bolts 3 8 24 thread Sun gear bushing swaging tool set Swaging tool Collar Sun gear bushing reamer set Sun gear shaft pilot Reamer and shaft assembly Holding fixture Bushing pilot body Self locking pin Center support bushing installer amp staking set Center support bushing staking tool Center support bushing installer Front support rear bearing remover Charging pump bearing installer Governor support pin installer Stator rivet or set Rivet punch staker Base plate Rivet remover pin Top plate 15 17 Copyright 1983 General Motors Corp 4 9 HT 740D HT 750D AUTOMATIC TRANSMISSIONS SPECIAL TOOLS Tool No Fig Item Description Ref Paragraph J 29198 3 58 Sealring groove gage J 29535 68 Turbine hub rivet or tool set J 29535 1 69 Base plate J 29535 2 70 Guide plate J 29535 3 73 Staking tool J 29535 4 72 Rivet remover tool J 29535 5 71 Drill guide J 29612 95 Valve body torque wrench J 33079 111 Forward clutch and shaft assembly lifter NR J 33080 4 101 Collet NR J 33080 7 102 Height gage NR J 33080 20 103 Bridge assembly NR J 33127 14 Selective snapring gage 7 30 7 7 Ab Y 67 Bolt 5 8 11 X 3 1 4 4 4 74 Bolt 1 2 13 X 3 1
414. t the selector lever into DR4 position Forward regulated pressure moves the 1 2 modulator valve upward in its bore compressing the valve spring late models The tickler spring at the bottom of the 1 2 shift valve forces the 1 2 shift valve upward permitting main pressure to pass through the valve forcing the spring loaded 1 2 relay valve to the bottom of its bore Priority main pressure is then directed to flow through the relay valve to the second clutch c First Gear Operation Shift the selector lever into Drive 1 DR1 position Hold pressure DH1 is directed from the selector valve to an area between the 1 2 shift valve and the 1 2 modulator valve This pressure moves the 1 2 shift valve to the bottom of its bore blocking main pressure flow to the 1 2 relay valve and maintaining first gear operation until the selector lever is moved or DH1 hold speed is exceeded d Reverse Gear Operation early models Shift the selector lever into R reverse position Reverse pressure from the selector valve is directed to three points the reverse signal valve pin pushing the valve pin and the 1 2 shift valve downward blocking main pressure to the top of the 1 2 relay valve This allows reverse pressure to pass through the bottom of 1 2 relay valve engaging fourth and first clutch Reverse pressure in the first trimmer trim boost area blocks the trimmer and prevents any trimming action e Reverse Gear Operation late models Shift the
415. tall thrust washer 5 onto the rear hub of front planetary carrier assembly 4 Install carrier assembly 4 so that thrust washer 5 seats on the front of center planetary carrier assembly 10 14 Install bronze thrust washer 3 sun gear 2 and bronze thrust washer 1 into the front of front planetary carrier assembly 4 6 23 PLANETARY CARRIER ASSEMBLIES NOTE The disassembly and assembly procedures for all planetary carrier assemblies differ only in the proper tool selection for the specific application The chart at the end of shows the tool number required for a specific application and identifies the carrier involved front center rear low lf the tool is common to all of the planetary carrier assemblies its number will be listed in the text If the tool is not common the text will refer to the chart For planetary carrier detailed information refer to the exploded views at the back of this manual a Assembly Inspection 1 Visually inspect planetary carrier assembly for evidence of excessive wear overheat indication damage or heavy metal contamination Copyright 1983 General Motors Corp 6 46 REBUILD OF SUBASSEMBLIES 2 Check end play of planetary carrier pinions With washer held flat insert feeler gage between carrier and thrust washer End play must be within 0 008 to 0 031 inch 0 203 to 0 787 mm NOTE Do not disassemble carrier assembly unless parts replacement is necessary Failure of one pin
416. tallation on both 2 valve and 4 valve cylinder head designs The 4 valve instructions are labeled 4 valve and the 2 valve instructions are labeled 2 valve If no heading is shown the instructions are applicable to both 4 Valve Head ENGINE PREPARATION Remove rocker cover and observe cylinder head arrangement Remove fuel supply and draintubes by nuts on injector and risers on back of cylinder head a Fa D ES 4 Valve Remove the rocker pedestal hold down bolts and disassemble the rocker pedestals and shafts Remove right hand exhaust rine bridges one per cylinder 4 Valve Remove ao screws and locknuts from engine bridges and insert them into Jacobs bridges 2 Valve Head haid 4 Valve Install jacobs salve onto bridge guides for right hand exhaust valves A 5 4 Valve Adjust exhaust valve binds as instructed in Detroit Diesel Maintenance Manual CAUTION LOCK LOCKNUT WITH BRIDGE IN VISE NOT ON ENGINE Tighten locknut to 20 25 Ib ft 27 34 N m torque e ME the oo a peas shafts If the engine IS equipped with rocker levers having an oil hole drill boss remove right hand exhaust rocker lever and grind off drill boss as shown The drill boss must be removed so that the Jacobs Brake slave piston will neun i 2 Valve Remove rocker me hold down bolts and disassemble the rocker pedestals and shafts CAUTION Loosen right hand exhaust valve push rod
417. tape CAUTION Inaccurate torque can cause leakage and cracked housings Tighten all pipe plugs to the torque specified in the assembly procedure and on the exploded views d Grease Used for Assembly Use oilsoluble grease with a low melting point petrolatum to temporarily retain parts stepjoint sealrings scarf cut sealrings and hooktype sealrings during assembly with mating parts CAUTION Do not use to retain cork gaskets e Sead i n g Compounds Nonsoluble Greases Do not use gasket type sealing compounds fibrous greases or nonsoluble vegetable base cooking compounds any place inside the transmission Do not use them any place where they could be flushed into the transmission hydraulic system However if adhesives or sealers are required for the oil pan gasket they may be applied on the pan mounting flange but only in the area outside of the flange bead f Lip type Seals 1 W h n replacing lip type seals make sure the spring loaded lip side is toward the oil to be sealed in toward the inside of the unit Coat the inside of the seal with high temperature grease MIL G 3545A or equivalent to protect the seal during shaft installation and to provide lubrication during initial operation 2 Dry sealing compound The circumference of some seals is precoated with a dry sealant The sealant is usually colored for easy identification The precoated seals do not require any additional sealant before insta
418. tch plate HT 750DRD 8 Install the ball bearing 28 A foldout 19 onto rear hub 27 of the low ring gear 9 Install a bearing race lip first and a needle bearing onto the rear inner diameter of the low carrier assembly fig 7 29 Install the rear race on the front hub of the low ring gear fig 7 29 Retain the bearing and two races with oil soluble grease 10 Install the low ring gear by carefully engaging the teeth of the gear with those of the four planetary pinions fig 7 29 c Rear Cover Assembly 1 Install a lifting bracket onto the threaded end of the output shaft lig 7 30 2 Install the rear cover gasket onto the rear cover ae Be sure the holes In the gasket align with those in the adapter housing Retain the gasket on the rear cover with oil soluble grease 3 Attach a hoist to the lifting bracket Install the rear cover as assembled TENIS onto the adapter housing fig 7 30 Since the two dowel pins in the cover are of different size installation is simplified f L NEEDLE BEAR ING Fd LOW PLANETAR YT E y if Ad Fa CARRIER ASSEN EE BC rm aen Fig 7 29 Installing low ring gear HT 750DRD Copyright 1983 General Motors Corp 7 15 HT 740D HT 750D AUTOMATIC TRANSMISSIONS HOIST LIFTING BRACKET AI 0 PUT SHAFT ut al LT BAL BEARING ADAPTER HOUSTNG 5299 Fig 7 30 Installing rear cover assembly HT 750DRD
419. ted to the front side of piston 12 clutch plates 22 and 29 are compressed together This locks forward clutch hub 19 to the forward clutch housing Since hub 19 is splined to the transmission main shaft the shaft will rotate with the hub at input speed 3 The simultaneous application of two clutches is necessary to produce one forward or o n e reverse gear The forward clutch is applied only in forward gears refer to a 1 2 above When the converter turbine rotates and the forward clutch is applied it drives the output shaft 4 Rotation of the oil pitot collector ring directs oil against the front pitot tube any time the converter turbine rotates Thus an increase in turbine speed produces a proportional increase in front governor pressure 2 12 FOURTH CLUTCH foldout 14 a Function Differs Among Models 1 The fourth clutch in the HT 740D or HT 747D has a dual function When engaged simultaneously with the forward clutch it produces fourth gear When engaged with the first clutch it produces reverse gear 2 In the HT 750CRD or HT 754CRD the fourth clutch has a dual function Engaged with the forward clutch it produces fifth gear Engaged with the low clutch it produces reverse gear 3 Inthe HT 750DRD the fourth clutch has a dual function Engaged with the forward clutch it produces fifth gear Engaged with the first clutch it produces reverse gear b Description The fourth clutch for all m
420. the tangs of the clutch plate are not subject to face wear the micrometer reading at a tang will be the original thickness Note that each clutch pack must contain one thick plate next to the piston and a basic number of thick and thin plates The combination of thick and thin plates are selected to meet the prescribed clearance with the clutch released Install all thick plates toward the piston end of the pack 2 Determine the wear on both internal and external plates refer to wear limits in Section 8 Replace worn plates Note that the thicknesses of external tanged plates in the low first second and third clutches in earlier models may be different from the thicknesses of corresponding plates in later models Wear limits stated in Section B are for plates presently supplied 3 If it is necessary to replace an external tanged plate be sure the plate thickness is identical to the original equipment Refer to b 1 and 2 above Keep the clutch packs separated do not mix the plates of one clutch with the plates of another 4 Clearance for all clutch plates is established during assembly procedure Clearances for the forward and fourth clutches are established during rebuild of those subassemblies in Section 6 7 3 ESTABLISHING CLUTCH CLEARANCES SELECTING CENTER SUPPORT SNAPRING HT 740D HT 747D a First Clutch Clearance 1 Before assembly the clutch clearance must be established One method is by direct
421. the earlier Model 71 92 engine brake Engine or engine brake failures Will result Those applications must continue to use the 064 slave piston setting A Jacobs Feeler Gauge 059 has been released The gauge P N is 007958 and can be obtained from any Jacobs Engine Brake Distributor With engine stopped and exhaust valves closed insert the 064 1 6 mm or the 059 1 49 mm feeler gauge between slave piston foot and exhaust valve bridge Turn adjusting screw in eu ur o 4 Valve until a slight aa ls felt on umm gauge Check both feet of slave piston and establish the setting under foot with minimum clearance Hold adjusting screw in this postion and tighten locknut to 15 18 Ib ft 20 24 Nem 2 Valve With engine yup and exhaust valves closed insert the 064 1 6 mm feeler gauge between slave piston feet and valve stem cap Turn adjusting screw in until proper clearance is achieved as indicated by a slight drag on feeler gauge Check both feet of slave piston and establish the setting under foot with minimum clearance Hold adjusting screw in this positon and Remove plug on back of head rim in the most convenient location closest to Engine Brake supply units For alternate installation method due to a recent Detroit Diesel blower mounted turbo bracket see Jacobs Service Letter 129 Connect with rubber wire support to fuel tubes closest to Engine Brake supply units as shown On 6V TE w
422. the gasket with oil soluble grease Be sure the holes in the gasket are aligned with those in the adapter housing EXTERNAL TANGEDn CLUTCH PLATE REAR CARRIFR 1 i i Y mns am iir 13 d Fig 7 18 Installing low clutch plates and ring gear HT 750CRD HT 754CRD 3 Attach a lifting bracket to the output shaft fig 7 20 Using a hoist guide the cover onto the adapter housing Since the two dowel pins in the cover are of different size cover to adapter installation is simplified i Lire E Bd H pP ENNETAB Y bo i j n BEN ain Cnt Gy NE FESR CLUTCH PLATES 13 ADAPTER HOUSING Fig 7 19 Low planetary carrier ring gear and clutch HT 750CRD HT 754CRD nist ADAPTER REAR COVER HOUSTNG GASKET ADAPTER HOUSING r Go ASK E 1 p n e amo WS Fig 7 20 Installing rear housing HT 750CRD HT 754 CRD Copyright 1983 General Motors Corp 7 11 HT 740D HT 750D AUTOMATIC TRANSMISSIONS BOLT 12 13 X 7 1 4 3 E OUTPUT SHAFT Lr p i a BOLT 12 13 X 5 314 21 V Lo 5304 7 Fig 7 21 Installing rear cover bolts HT 750CRD HT 754CRD HT 750DRD 4 Install twentyone 1 2 13 x 5 3 4 inch bolts and three 1 2 13 x 7 1 4 inch bolts and washers to retain the rear cover fig 7 21 Tighten the bolts to 67 80 Ib ft 90 108 N m 5 Install the governor assembly into the rear cover by rotating it counter clockwise
423. the grease in which new bearings are packed 3 Do not lay bearings on a dirty bench place them on clean lint free paper 4 If assembly is not to be completed at once wrap or cover the lubricated bearings with clean paper or lint free cloth to keep out dust e Inspecting Cast Parts Machined Surfaces 1 Inspect bores for wear scratches grooves and dirt Remove scratches and burs with crocus cloth Remove foreign matter Replace parts that are deeply scratched or grooved 2 Inspect all oil passages for obstructions If an obstruction is found remove it with compressed air or by working a soft wire back and forth through the passage and flushing it out with mineral spirits 3 Inspect mounting faces for nicks burs scratches and foreign matter Remove such defects with crocus cloth or a soft stone If scratches are deep replace the defective part 4 Inspect threaded openings for damaged threads Chase damaged threads with the correct size used tap a new tap can cut oversize 5 Inspect the ribs inside the main housing for reaction c 1 u t c h plate wear grooves in the s i d e of the ribs Replace housings that have wear tsi beyond wear limits Refer to wear limits table 8 11 6 Replace housings or other cast parts that are cracked 7 Inspect all machined surfaces for damage that could cause oil leakage or other malfunction of the part Rework or replace the defective parts 8 Inspect the oil tracks
424. the housing is cold Heat the housing slightly if necessary Do not use a torch to heat the housing A sun lamp or a current of warm air is sufficient 1 Install the third clutch piston assembly into the center support The lips of the sealrings must be toward the cavity in the center support CAUTION Improper installation of butt joint sealrings may cause transmission failure Refer to paragraph 4 6g for proper installation procedure 2 Install the butt joint sealrings onto the center support hub Attach lifting bracket J 24195 and install the center support assembly Align the tapped hole in the support to the hole in the transmission housing fig 7 24 52983 Fig 7 31 Installing second clutch snapring 3 Install the special 3 8 16 x 3 inch 2 1 4 inch in earlier models bolt and plain washer finger tight Remove the lifting bracket NOTE It may be necessary to compress the center support to install the selective snapring 4 Install the selective snapring 77 3b 7 above that retains the center support fig 7 25 Be sure the gap of the snapring is at the top of the transmission housing regardless of its position when removed 7 11 INSTALLING THIRD FOURTH FORWARD CLUTCHES NOTE Two methods of checking clutch plate clearance have been established One method is by direct measurement as outlined in items 4 and 5 below The alternate method is by stack dimension computation outl
425. the switch and switch actuator activate the switch Remove plunger from Jacobs butter screw and install lock nut removed from Engine buffer screw Insert Jacobs buffer screw into govemor housing to approximately the same depth as Engine buffer screw Start engine and adjust buffer screw in accordance with the Detroit Diesel Manual as follows With the Idle speed properly set adjust the buffer screw as follows 1 With the engine running at normal operating temperature turn the buffer screw in so It contacts the differential lever as lightly as possible and still eliminates engine roll NOTE Do not increase the engine Idle speed more than 15 rpm with the buffer screw 2 Recheck the maximum no load speed If It has increased more than 25 rom back off the buffer screw until the increase is less than 25 rom 3 Holdthe Adis screw and tighten lock nut i Shut down engine pm insert buffer switch yes into buffer Screw Attach buffer m to y buffer screw pum Switch to clear other engine components Ai Lisa Lock buffer switch ocr nut ms holding switch in position FAST IDLE BUFFER SWITCH INSTALLATION A fast idle buffer switch may be purchased for buffer switch installations on Series 71 and 92 Detroit Diesel Engines containing last ldle air cylinders This type switch must be installed to retain the fast idle feature in conjunction with automatic Engine Brake operation If the engine Is dag Wit a f
426. tight maintaining a parallel position between the puller body and converter pump 18 Using a wrench tighten the forcing screw until the converter pump and ground sleeve separate Remove the pump b Scavenge Pump Assembly 1 Position the transmission horizontally bottom side downward Remove bolt Aj foldout 12 from the suction tube retaining clip on the scavenge pump fig 5 25 2 Remove three bolts and washers that retain the scavenge pump assembly fig Remove tne the pump assembly Refer td paragraph 6 14 for rebuild of the pump assembly c Power Takeoff 1 Remove the bolt that retains the PTO idler gear spindle fig 5 26 SCAVENGE PUN LOCKWASHER 3 8 3 esr SUCTION wE 86 SUCTION TUBE Ww RETAINING CLIP Sarig Fig 5 25 Removing scavenge p assembly Lue reprae ns o A A nah ae TU LEA I 1 LCS Fig 5 26 Removing top PTO gear retaining bolt 2 Use slide hammer and adapter J 24171 2 i remove remove the spindle and gear assembly Press the spindle from the t m the gear is damaged replace the gear assembly Refer MISC ae Copyright 1983 General Motors Corp HT 740D HT 750D STIMA Pet i Yr Hu e ET Ten uL T 7 bu d A E den in E Ds e 1 e tum 1x rn are PTO SPIN D LE ADAPTER SIDE PTO GEAR BOLT 1 2 20 X 3 3 4 LOCKWASHER 1 2 PLAINWASHER 1 2 SIDE PTO COV
427. to 81 97 lb ft 110 131 Mm Tighten the remaining five bolts to 67 80 Ib ft 90 108 Nm 6 Install the pitot tube screws and washers as each guide bolt is removed fig 7 39 Tighten the screws to 3 4 Ib ft 4 5 Nem 7 Install eleven 1 213 x 2 inch bolts with lockwashers through the front flange of the transmission housing into the rear of the converter housing some bolt holes may be blocked by mounting fixture install bolts when removed from fixture Tighten the bolts to 67 80 Ib ft 90 108 Nem 8 For transmissions equipped with a power takeoff at the top and or side of the converter housing continue assembly as applicable in the following steps 9 On earlier models install the PTO idler gear assembly 30 A foldout 12 onto the spindle near the bottom of the converter housing Install retainer 29 lockwasher 28 and bolt 27 to retain the gear assembly Tighten the bolt to 83 100 Ib ft 113 135 Nm On later models install gear assembly 30 foldout 12 into the converter housing Install sealring 34 A foldout 11 onto spindle 35 Coat the spindle with oil soluble grease Align the gear with the spindle bore in the housing Install spindle 35 by driving it forward with a soft mallet until its larger diameter seats against the inner race of the bearing in the gear Install lockwasher 45 and the 1 2 20 x 3 3 4 inch bolt 46 to retain the spindle Tighten the bolt to 83 100 Ib ft 113 136 Nm 10 Install the PTO idl
428. to the converter P housing fig 7 36 Raise the converter housing NEC TM assembly above the transmission TRANSMISSIE HiS 15 33040 Fig 7 36 Installing converter housing assembly Copyright 1983 General Motors Corp 7 20 ASSEMBLY OF TRANSMISSION 4 Install two 1 2 13 x 2 3 8 inch guide screws J 1126 1 one in the converter housing and one in the transmission housing fig 7 36 5 Install two 10 32 x 6 inch guide screws J 6889 1 into the pitot tube Exit port of pitot tube must face toward guide bolts fig 7 36 Install the pitot tube and guide bolts so that the guide bolts enter the screw holes in the converter housing and entrance port of pitot tube faces outward toward pitot collector ring 36 6 Install the converter housing onto the transmission housing using care to avoid damage to the pitot tube and the collector ring fig 7 36 7 Install seven 1 2 13 x 2 inch bolts and washers at the inside of the converter housing 38 Tighten the bolts 67 80 Ib ft 90 108 Nm 8 Install the pitot tube screws and washers as each guide bolt is removed fig 7 39 Tighten the screws to 30 48 in Ib 3 4 5 4 Nem 9 Install nine 1 2 13 x 2 inch bolts with washers through the transmission housing into the converter housing fig 7 37 The two remaining bolts and washers cannot be installed until the mounting bracket is removed Tighten the bolts to 67 80 Ib ft 90 CONVERTER HOUSING BOLT
429. transmission with oil Excessive oil causes overheating and irregular shift patterns If the oil level is too low the result can be poor performance clutches will not receive adequate oil supply CAUTION A dipstick that anchors inside the top end of a non vented filler tube can draw oil up into the tube during removal and give an inaccurate reading on the dipstick b Foaming and Aerating 1 Transmission performance will be affected when the oil foams or aerates Foaming or aeration is normally caused by low oil in the sump too much oil in the sump or a defective or missing sealring on the intake pipe 2 A low oil level will not completely envelop the oil filter Therefore oil and air is drawn by the input pump and is directed to the clutches and converter causing converter cavitational noises and irregular shifting The aeration also changes the viscosity and color to a thin milky liquid 3 The oil levels are established as shown in Tare Sand Previously only add and full levels were established illustrates the six seven and eight and one half inch dipstick configurations 4 A defective sealring 34 B foldout 16 on the filter intake pipe will cause the input pump to draw air into the oil system Air thus entering the oil will result in the conditions described in 2 above Protect Fill Pipe When adding oil or checking oil level dirt or foreign material must not be allowed to enter the fill pipe Before
430. transmissions are of primary concern to Detroit Diesel Allison its distributors and their dealers As an owner of an Allison transmission you have service locations throughout the U S and Canada plus many outlets worldwide that are prepared and eager to meet your parts and service needs with Expert service by trained personnel e Emergency service 24 hours a day in many areas Complete parts support e Sales teams to help determine your power requirements Product information and literature We recognize however that despite the best intentions of everyone concerned misunderstandings may occur Normally any such situation that arises in connection with the sale operation or service of your transmission will be handled by the distributor or dealer in your area check the Yellow Pages for the Detroit Diesel Allison service outlet nearest you To further assure your complete satisfaction we have developed the following three step procedure to be followed in the event you have a problem that has not been handled satisfactorily otep One Discuss your problem with a member of management from the distributorship or dealership Frequently complaints are the result of a breakdown in communication and can quickly be resolved by a member of management If you have already discussed the problem with the Sales or Service Manager contact the General Manager If your problems originate with a dealer explain the matter to a
431. tube 3 4 5 FIT 750 26 Low signal tube 2 3 4 shift assist tube clip 28 3 4 shift assist tube 29 Signal tube 30 Bolt 5 16 18 x 1 5 8 E 31 Plain washer 5 16 32 Oil filter spacer 2 33 Oil filter 34 Sealring 35 Plug 36 Washer 37 Plug 38 Oil pan gasket 39 Drain plug C 40 Drain plug washer 41 Oil pan 42 Washer head screw 5 16 18 x 5 8 23 F 43 Inside detent lever assembly 44 Locknut 3 8 F 45 Modulator valve actuator pin 46 Bolt 5 16 18 x 9 16 P 47 Modulator to housing retainer 48 Shaft retainer pin 49 Washer 50 Pipe plug 3 4 B 51 Shaft seal 52 Pipe plug 1 8 B 53 Manual selector shaft assembly 54 Manual selector shaft 55 Manual selector shaft nut C 56 Nut 1 2 20 3 retarder models A 5 Lockwasher 1 2 3 58 PTO cover gasket 59 PTO cover 60 Washer 6 61 Bolt 3 8 16 x 3 4 6 C 62 Lockwasher 1 2 8 retarder models 63 Bolt 1 2 13 x 6 8 retarder models A Torque Ib ft N m A 67 80 91 108 B 4 5 5 7 C 15 20 20 27 D 9 11 12 15 E 13 16 18 22 F10 1314 18 HT 740D HT 750D AUTOMATIC TRANSMISSIONS FOLDOUT 16 113590 A Foldout 16 Gear unit and main shaft assembly HT 750DRD exploded view B Foldout 16 Transmission housing oil filter and six inch deep oil pan exploded view Copyright 1983 General Motors Corp 1 Breather 2 Lockwasher 1 2 11 non retarder models 3
432. ue crc OD OT NUTS Faea i t Ey D ke E Dl te cur he Aer dens T FLANGE NUT FROM FILTER SELECTOR SHAFT NEUTRAL gt START SWITCH LOCATION HEAR GOVEHNOR COVER REAR GOVEHNOR MODULATOR PRESSURE ACTUATOR OPENING GIL DRAIN PLUG 51516 Fig 1 1 Model 7400 transmission left rear view TU CDULER TEMPERATURE i 7 SENSOR PORT MOUNTING BREATHER FROM COOLER NAMEPLATE TOROUE STARTER GEAR CONVERTER FLYWHEEL REVERSE SIGNAL POURTH GLUTCH SWITCH LOCATION PRESSURE TAP 81917 Fig 1 2 Model HT 740D transmission right front view Copyright 1983 General Motors Corp GENERAL INFOR i V XT 4 MOUNTING FQURTH CLUTCH I FROM TORQUE STARTER RING PRESSURETAP _ COOLER CONVERTER Fig 1 4 Model HT 750 transmission right front view Copyright 1983 General Motors Corp 1 3 Fig 1 6 Model HT 750 transmission right front view with retarder Copyright 1983 General Motors Corp 1 4 GENERAL INFORMATION 4270 io zn 1 S4271 Fig 1 8 Model HT 750 transmission right rear view with dropbox Copyright 1983 General Motors Corp 1 5 HT 740D HT 750D AUTOMATIC TRANSMISSIONS Transmission Manvfactured By xD Detroit Diesel Allison Division of General Motors Corporation indiana u Fig 1 9 Transmission name plate 1 4 GENERAL DESCRIPTION a Automatic Shifting Automatic
433. until the outer end of the shaft is 1 29 to 1 33 inches 32 8 to 33 8 mm from the outer steel face of the shaft oil seal EI 6 101 6 33 ESTABLISHING CLUTCH CLEARANCES a Two Methods 1 Either of t w o methods may be used to establish the proper clutch clearances clutches released One method is by direct measurement This method is incorporated in each clutch assembly procedure relating either to subassembly rebuild transmission assembly cod para 6 13 and 7 11 The second method is by stack dimension computation which may be more convenient when quantity or assembly line overhaul practices are used 2 Subparagraphs b through f below outline the stack dimension computation method for each clutch NOTE The stack methods outlined require t h a t clutch plates be new The specified load must be evenly distributed over the entire clutch pack Is Forward Clutch 1 Stack the forward clutch plates and fourth clutch hub as shown inj figure 6 107 2 Apply the specified load and measure dimension X 3 From the table in figure 6 107 select the forward clutch piston Use the parts measured and the selected piston ins the forward clutch assembly c Fourth Clutch 1 Stack the fourth clutch plates and backplate as shown figure 6 108 Copyright 1983 General Motors Corp REBUILD OF SUBASSEMBLIES 980 1020 18 LOAD d 6834685 1 MEM S DIM
434. uous and includes all models Where procedures apply to specific models they will be identified as to model b When a procedure does not apply to the specific model being disassembled go to the next procedure which is applicable C Certain illustrations will not always illustrate the model being disassembled but when the operation is identical the illustration will correctly illustrate the procedure 5 2 REMOVING EXTERNAL COMPONENTS a Mounting Transmission In Overhaul Stand 1 Overhaul stands and mounting of the transmission therein will vary shows the transmission installed in a typical overhaul stand 2 Beforeinstalling the lifting bracket onto the transmission remove any bolts which cannot be removed due to obstruction by the bracket b Hemoving External Components 1 Remove the output flange Paragraph 3 14 a explains the removal procedure for flanges retained with a self locking nut 2 On models having a two bolt top cover on the converter housing remove two bolts 13 B foldout 10 two washers earlier model only cover 14 and gasket 15 3 models having an eight bolt top cover and an eight bolt side cover on the converter housing remove eight bolts 24 41 A foldout 11 eight washers 23 42 covers 22 43 and gaskets 21 44 NR TOP PTO i o COVER 3 RETARDER FLANGE RETAINER di EE i WS VALVE NUT gato x il y d OVERHAUL ud d x cid BO
435. ure closed throttle will delay downshifts 2 any automatic downshift the shift signal valve a c t s first This exhausts the shift signal holding the relay valve downward The relay valve then moves upward exhausting the applied clutch and applying the clutch for the next lower gear S Downshift and Reverse Inhibiting 1 Inherent in the system as a result of valve areas and pressure calibrations is a means for preventing downshifts at a too high vehicle speed or a reverse shift at an excessive forward speed 2 Progressive downshifts occur because the regulated hold pressure is calibrated along with the valve areas to shift the signal valves downward against rear governor pressure only when the governor pressure decreases to a value corresponding to a safe downshift speed Thus if speed is too great rear governor pressure is sufficient to hold the shift signal valve upward against hold pressure As rear governor pressure decreases the shift signal valves move downward in sequence 2 32 TORQUE PATHS THROUGH TRANSMISSION HT 740D HT 747D a Converter Operation Power is transmitted hydraulically through the torque converter The engine d r i v e s the converter pump Thepump throws oil against the vanes of the turbine imparting torque to the converter turbine shaft From the turbine oil flows between the vanes of the stator and re enters the pump where the cycle begins again When the engine is idling imp
436. ushing Do not damage the bushing bore during removal Attach handle J 8092 to bushing installer J 24371 Place the new bushing on the installer and install the bushing into its bore in the sun gear If an installer tool is not available press the bushing into its bore 0 100 below the face of the gear b o 6 25 ADAPTER HOUSING ASSEMBLY HT 750 a Disassembly B foldout 18 18 1 Position adapter housing and piston assembly 2 piston assembly upward Lift out the piston assembly includes items 3 through 8 2 Remove the inner and outer sealrings from the piston fig 6 69 3 urn the piston assembly over and cut the four retainer rings while depressing the retainer 6 70 TI P hs 2t Z TEAL ak je rg Fi f E D 4 d i m F K ae m M a OE i ze M E AER ier Pr LET en DEP TY SES s E 3 j PISTON SPRING 128 52955 Fig 6 69 Removing or installing first clutch piston seal rings HT 750 NOTE Any method of removal except cutting may damage the risers on the piston Damage w i 11 lessen the holding power of retainer rings installed thereafter 4 Remove the spring retainer and twenty eight spring s from the piston fig 6 70 5 If replacement is necessary remove dowel pins 11 and 12 and orifice plug 13 foldout 18 from adapter housing 10 NOTE Refer to above b Assembly B foldout 18
437. ustration foldout 18 2 B foldout 18 10 15 15 15 16 16 A foldout 19 10 14 14 14 15 15 20 foldout 19 10 A foldout 20 14 22 29 Part Number 6835748 6834487 6880727 6837467 6835748 6834487 6880727 6834680 6834766 6837467 6835748 6834487 6880727 6834680 6834766 6883007 6880232 23016853 6885572 6836272 WEAR LIMITS AND SPRING DATA Table 8 1 WEAR LIMITS cont Description FIRST CLUTCH cont Internal splined clch plate thickness Internal splined clutch plate thickness Internal splined clutch plate thickness ADAPTER HOUSING LOW CLUTCH PLATES Adapter housing reaction clutch plate tang groove depth Internal splined clutch plate thickness Internal splined clutch plate thickness Internal splined clutch plate thickness External tanged clutch plate Thickness Cone External tanged clutch plate Thickness Cone Low clutch clearance refer td_para 7 4 ADAPTER HOUSING LOW CLUTCH PLATES Adapter housing reaction clutch plate tang groove depth Internal splined clutch plate thickness Internal splined clutch plate thickness Internal splined clutch plate thickness External tanged clutch Thickness Cone External tanged clutch Thickness Cone Low sun gear and hub bushing clearance on output shaft 35 B foldout 19 ADAPTER HOUSING LOW CLUTCH PLATES Adapter housing reaction clutch plate tang gro
438. utch Rear Planetary Ring Gear 1 Place the rear planetary ring gear short splines rear downward on a bench Install ten of the plates from the clutch pack removed in 7 4c 5 above or from the first clutch components selected by the stack method as follows Lay aside the first three plates from the piston end of the pack refer to para 7 20 Starting with the fourth plate in the pack internal splined alternately install five internal splined and five external tanged plates onto the ring gear 2 Align the external tangs of the plate pack Carefully invert the ring gear and plate pack and install the assembled parts into the rear of the transmission housing 3 Install the three remaining plates of the pack external tanged internal splined external tanged sequence NOTE Last plate installed must be a thick plate 4 Place the adapter housing with piston front downward onto the transmission housing 5 Install compressor bar J 24208 3 onto the adapter housing fig 7 14 Retain it with two 1 2 13 x 5 3 4 inch bolts 6 Position the transmission with the front upward Copyright 1983 General Motors Corp ASSEMBLY OF TRANSMISSION HOLST MAIN SHAFI ames TRANSMISSION uma HOUSING Le 24208 3 329 __ BOLT 1 2 13 X 5 344 2 E 52989 Fig 7 14 Installing gear unit assembly HT 750CRD HT 754CRD 7 Remove the center support snapring and anchor bolt Attach bracket J 2
439. utch Pack Procedure Sleeve Retaining Compound 6 3 FL YWHEEL LOCKUP CLUTCH CONVERTER TURBINE a Disassembly 6 1 b Rebuilding Converter Turbine Assembly C ASSOMDIY 6 4 6 4 TORQUE CONVERTER STATOR ASSEMBLY Disassembly Unna 6 5 b Rebuilding Stator Assembly 2 2 C ee E EE 6 7 6 5 TORQUE CONVERTER PUMP ASSEMBLY a b 22 2 2 6 8 Paragraph Page 6 6 CONTROL VALVE BODY ASSEMBLY a Disassembly 6 9 NEP ne eee eee 6 12 6 7 LOW TRIMMER VALVE BODY ASSEMBLY HT 750 a Disassembly 6 15 b Assembly 6 16 6 8 LOW SHIFT VALVE BODY ASSEMBLY HT 750 a Disassembly b Assembly 6 16 6 9 LOCKUP CUTOFF VALVE BODY ASSEMBLY a Disassembly b Assembly 6 17 6 10 CONVERTER HOUSING WITH 2 BOLT TOP COVER FRONT SUPPORT OIL PUMP a Disassembly 6 17 b Assembly
440. utput Transfer Housing dropbox fig 1 7 and 1 8 Transmissions which have the suffix DB in their model designations include a dropbox transfer gear housing at the rear instead of having the output shaft in line with the input shaft The drop box provides an in line output and a front and or rear output below the input center line at a radius of 20 inches 508 mm It also provides five angular output positions 1 directly below center line 2 below and 15 degrees to the left of vertical center below and 30 degrees to the left 4 below and 45 degrees to the left 5 below and 60 degrees to the left i Output Disconnects Output disconnects are available on all dropbox models Any desired combination of disconnects can be assembled Rear disconnects are shown in figures 1 7 and 1 8 A front disconnect is shown on foldout 23 1 5 OPERATING INSTRUCTIONS Refer to Drivers Handbook SA 1334 a Vehicle Related Controls For information on controls which are related to the vehicle refer to the vehicle service manual b Neutral N Place the shift selector at the neutral position before starting the engine A neutral safety s w i t c h on the transmission or in the selector linkage prevents starting the engine while the selector lever is not at neutral Apply the vehicle brakes and shift to neutral any time the engine is to be running while the operator is not at the controls c Forward Drive Ranges
441. vernor accumulator valve is a spring loaded valve In a straight bore The accumulator valve absorbs pressure surges and provides a more uniform governor pressure h Modulator Pressure Circuit foldouts 5 6 7 8 1 The modulator valve produces a regulated reduced pressure which is derived from m a i n pressure The valve is moved rightward by a spring at the left end of the valve when the throttle is closed The valve is moved leftward by the cam and spring action when the throttle is opened When the spring force at the left of the valve is in balance with the spring force and modulator pressure at the right end of the valve modulator pressure is regulated 2 When the throttle setting is increased the movement of the actuator cam forces the modulator valve toward the left This leftward movement reduces modulator pressure When the throttle setting is reduced the downward movement of the actuator cam allows the spring at the left end of valve to return the valve to another regulating position Thus modulation pressure varies with throttle opening 3 At all the shift signal valves modulator and governor pressures act on calibrated a r e a s to upshift the valves against calibrated springs Each of the shift valves and springs is calibrated to insure that the valves will shift at the proper time and in proper sequence At a given governor pressure an increase in modulator pressure will upshift a signal valve A decrease in
442. vernor pressure from upshifting the signal valves unless a governor pressure well above that normally attained is reached This pressure isa regulated reduced pressure derived from main pressure at the hold regulator valve Main pressure is directed to the hold regulator valve through the hold feed line when the selector valve is at D3 D2 or D1 position The pressure produced in the hold regulator valve is directed to the 3 4 shift signal valve when the selector valve is at drive 3 The hold pressure is directed to the 2 3 and 3 4 shift signal valves when the selector valve is at drive 2 position The pressure is directed to all three shift signal valves 3 4 2 3 and 1 2 when the selector valve is at drive 1 position 8 Hold regulator pressure at each shift signal valve will push the upper valve upward and raise the pressure at which the lower valve will be pushed upward by rear governor pressure Thus when hold regulator pressure is present an upshift can occur at that shift signal valve but only at an elevated speed o Clutch Circuit Drive Ranges HT 750CRD HT 754CRD foldout 6 1 There are six clutches the transmission These are low clutch first clutch second clutch third clutch fourth clutch and forward clutch The clutches are applied for various conditions as follows 2 Condition Clutch es applied Neutral LOW First gear Low and forward Second gear First and forward Third gear Second and forward
443. verse gears transmitting torque directly to the output shaft Low planetary is required to produce first gear only b Operation A foldout 16 1 Compounding front a n d center planetary assemblies 5 16 used in conjunction with the forward and second clutches produces third gear when the forward and second clutches are applied Hig 2 18 2 The center planetary is active in third fourth fifth and reverse gears 3 Therear planetary carrier assembly 39 A is used in all gears In first gear it works combination with the 1 o w planetary to produce a high output torque In second gear it acts alone to transmit torque at a reduction to the output shaft In third fourth and fifth gears its only function is to transfer torque to the output shaft In reverse gear it transmits torque at a reduction to the output shaft 4 The low planetary carrier assembly 29 foldout 19 has only one function first gear With the application of forward and low clutches torque is transmitted through the main shaft to the rear planetary sun gear splitting at this point sends torque through the rear carrier to the output shaft and through the low sun gear carrier pinions and ring gear to the output shaft This interconnection between the two carriers causes a compounding action producing a high output torque NOTE In fifth gear because both the forward and fourth clutches are engaged a 11 four planetaries rotate as aunit T
444. verter stator Torque converter pump Accessory cover Torque converter housing Transmission input pump Forward support and valve assembly Forward clutch assembly Fourth clutch assembly Third clutch Sun gear and shaft assembly Center support housing assembly Main shaft assembly Second clutch Transmission housing Front planetary carrier assembly Center planetary carrier assembly Rear planetary carrier assembly First eluteh Rear cover assembly Governor drive gear Speedometer drive gear Output shaft assembly Output flange retainer nut Gear unit onnecting drum Control vaive body assembly Oil filter Oil transfer plate Oil pan Pitot tube Flywheel PTO drive gear HT 740D HT 750D AUTOMATIC TRANSMISSIONS p Foldout 1 Model HT 740D HT 747D transmission cross section view Copyright 1983 General Motors Corp FOLDOUT 1 9 10 11 12 13 14 15 16 1 18 19 20 21 EMITE um i MM O E See Hm 31 30 29 28 53014 oss Section view OO 0 UF amp r5 Starter ring gear Lockup clutch Torque converter turbine Torque converter stator Torque converter pump Accessory cover Torque converter housing Transmission input pump Forward support and valve assembly Forward clutch assembly Fourth clutch assembly Third eluteh Sun gear and shaft assembly Center support housing assembly Main shaft assembly Seeond eluteh Transmission housing Front
445. w 14 0 0 054 0 560 1 99 0 84 8 10 to 9 90 valve orange stripe 1 37 14 2 50 6 21 3 36 0 to 44 0 12 Low shift signal 6778156 No color code 11 5 0 041 0 440 1 45 0 80 4 30 to 4 50 valve 1 04 11 2 36 8 20 3 19 1 to 20 0 6838285 Solid yellow 8 0 0 041 0 501 1 10 0 69 2 57 to 3 13 orange stripe 1 04 12 7 27 9 17 5 11 4 to 13 9 6838340 Solid orange 12 0 0 038 0 450 2 08 1 09 4 00 to 4 50 0 97 11 4 52 8 27 7 17 8 to 20 0 6838341 No color code 11 0 0 041 0 450 1 95 1 09 4 90 to 5 40 1 04 11 4 49 5 27 7 21 8 to 24 0 6880154 Solid white 11 0 0 041 0 450 1 88 1 90 4 55 to 4 95 6838342 Solid yellow 12 0 0 038 0 450 1 98 1 09 3 60 to 4 10 white stripe 0 97 11 4 50 3 27 7 16 0 to 18 2 yellow stripe 1 04 11 4 47 8 27 7 20 2 to 22 0 6880155 Orange stripe 12 0 0 038 0 450 1 80 1 09 2 90 to 3 20 0 97 11 4 45 8 27 7 12 9 to 14 2 6880186 Solid yellow 12 0 041 0 464 1 37 0 89 2 43 to 2 69 blue stripe 1 04 11 8 34 8 22 6 10 8 to 12 0 6881036 Solid yellow 9 0 0 044 0 501 1 16 0 69 3 37 to 4 13 white stripe 1 12 12 7 29 5 17 5 15 0 to 18 4 23012820 Solid yellow 14 0 038 0 450 1 51 1 09 1 42 to 1 58 0 97 11 43 38 4 27 7 6 3 to 7 0 24 Low shift trimmer 6833938 Solid green 12 5 0 080 0 940 2 96 1 10 8 30 to 10 30 valve primary 2 03 23 9 75 2 27 9 36 9 to 45 8 6833940 oolid blue 8 5 0 121 0 950 2 38 1 94 29 00 to 35 00 orange stripe 3 07 24 1 60
446. ward clutch release spring 20 14 Spring retainer 15 External snapping 16 Thrust bearing race 17 Roller bearing assembly 18 Thrust bearing race 19 Forward clutch hub 20 External tanged clutch plate 5 21 Internal splined clutch plate 5 22 Fourth clutch driving hub 23 Internal snapping 24 Thrust bearing race 25 Roller bearing assembly 26 Thrust bearing race HT 740D HT 750D AUTOMATIC TRANSMISSIONS A Foldout 13 Front support and valve assembly exploded view 11343 Copyright 1983 General motors Corp 9239C B Foldout 13 Forward clutch assembly exploded view FOLDOUT 13 A 1 Fourth clutch assembly 2 Snapring 3 Clutch backplate 4 Internal splined clutch plate 5 5 External tanged clutch plate 5 6 Snapring 7 Spring retainer 8 Clutch release spring 20 9 Fourth clutch piston marked M 1 110 1 120 THK S 1 137 1 147 THK T 1 164 1 174 THK 10 Piston outer sealring 11 Clutch housing sealring 12 Fourth clutch housing assembly 13 Ball 3 16 8 14 Fourth lutch housing 15 Thrust bearing race 1 Snapring 2 Third clutch backplate 3 Internal splined clutch plate 4 4 External tanged clutch plate 4 0 0993 0 1063 THK Red AR 0 1161 0 1231 THK Green AR 5 Snapring 1 0 148 3 76 mm 0 150 3 81 mm 0 152 8 86 mm 0 154 3 91 mm 0 155 3 94 mm 0 157 3 99 mm 0 158 4 01 mm 0 160 4 06 mm 6 Self
447. will vary depending on the condition of the swaging tool and the press equipment being used Copyright 1983 General Motors Corp REBUILD OF SUBASSEMBLIES 9 zm um 7 mnt nk aum mmm LS i x Qe read pan Ec UE Y m GEL d s 1 25587 1 Y i CARERE i LUE M n 12912141 BOLT 5 8 11X3 25 Jani M STATOR d ASSEMBLY md IN ri mo Mm j e n l PR ML a en STO Ba I SEED Pii E prn urtica EE Pr E 84401 Fig 6 13 Staking stator rivet 15 Apply approximately 8000 pound 3629 kg load to swage each rivet head Swage the second rivet 180 degrees from the first Locate the third rivet 90 degrees from the second etc until all rivets are swaged 16 Remove the top and bottom plate retaining bolt from stator assembly 13 A foldout 10 Remove the two plates c Assembly foldout 10 1 Place stator assembly 13 on the work table rear side upward Install thrust bearing race 22 into the stator 2 Coat the pockets of stator assembly 13 stator springs 20 and rollers 21 with oil soluble grease 3 Install stator roller holder J 24218 2 into the stator against the thrust bearing race installed in 1 above fig 6 14 4 Install ten freewheel roller springs into the stator cam pockets The I ya ME ipa Vel EU E REEL T Nod rt
448. with the governor bore in the adapter assembly is critical The governor must rotate freely and without interference with either the adapter bore or the pin Any interference will result in damage to the governor body the bore in the adapter or the governor driven gear 2 If governor support pin 13 was removed LM In a new pin to the dimension shown in figure 6 3 If removed install plugs 12 B foldout 19 Tighten the plugs to 10 to 12 Ib ft 13 6 to 16 3 N m 4 Grease and install inner sealring 7 and outer sealring 6 into the sealring grooves of piston 5 Lips of the sealrings must be toward the rear of the transmission 5b Place adapter assembly 9 piston cavity upward on the work table 6 Using inner seal protector J 24210 carefully install low clutch piston 5 B foldout 19 spring guide bosses upward into the piston cavity Make sure that the lips of the sealrings face the bottom of the piston cavity 7 Install thirty piston return springs 4 onto the guide bosses of the piston Install spring retainer 3 outer lips toward the piston onto the springs 8 Compress the spring retainer until it is clear of the snapring groove in the adapter hub Install snapring 2 9 Invert the adapter assembly so it is resting piston downward on blocks 10 Coat the outer diameter of oil seal 11 Bjfoldout 19 wi th nonhardening sealer and the inside diameter with a high temperature grease Reference par
449. x lockstrips 28 14 Tighten the bolts to 33 40 Ib ft 45 54 Nem Bend the corner of each lockstrip to retain the twelve bolts fig 6 17 15 Install sealring 31 onto the outside diameter of converter pump assembly 32 6 6 CONTROL VALVE BODY ASSEMBLY CAUTION The valve body assembly contains a number of springs some of which are similar and can be mistakenly interchanged Also springs vary in v a 1 v e bodies u s e d on different models If the springs are not reinstalled in the s a m e locations from which removed erratic shift patterns may occur For these reasons it is recommended that each spring at removal be tagged with its item number in B foldout 20 This will simplify correct assembly of the valve body components a Disassembly B foldout 20 1 Place valve assembly 1 foldout 20 on the work table modulator valve body 28 upward Heference figure 6 18 2 If not previously removed remove manual selector valve 80 or 81 Stop bolt 70 must be removed before valve 81 can be removed 3 Remove three bolts 17 that retain modulator valve body 28 Remove control valve body 30 while holding oil transfer plate 7 and separator plate 29 together 4 Invert the oil transfer and separator plates separator plate on top while holding them firmly together Place them on the work table Copyright 1983 General Motors Corp 6 9 HT 740D HT 750D SERIES TRANSMISSIONS 31353 Fig 6 18 Compo
450. y separate the dropbox from the adapter and at the same time use a soft mallet to keep the output drive shaft assembly from pulling upward with the dropbox fig 5 4 4 Remove twenty four bolts 18 and 25 and lockwashers 19 and 24 Lift off the dropbox Transfer drive gear 2 A foldout 22 will remain with the drive shaft b Refer to paragraph 6 28 for rebuild of transfer gear housing dropbox components NOTE Remove transmission output shaft assembly 32 or 38 B 19 only if further disassembly of transmission is necessary 6 If shaft assembly 38 is used pry up staked portion of nut 43 B ffoldout 19 and remove the nut 7 Carefully remove g e ar 2 A foldout and attached bearings 1 and 3 from the shaft 8 Remove twenty two bolts 21 foldout 19 and two bolts 22 and lockwashers 20 and 23 9 With a hoist and a three strand sling lift off transfer gear housing adapter assembly 9 CAUTION Rear adapter housing assembly 9 A foldout 19 is h e 1 d in place by the same bolts as the transfer gear housing adapter 9 B foldout 19 The adapter housing should be held while removing the transfer g ear housing adapter 10 foldout 19 housing 11 Replace transfer gear adapter assembly 9 foldout 19 onto the a and retain it with four bolts 21 B foldout 19 Remove output shaft assembly 32 B NOTE Further disassembly procedures a p p 1 y to both dropbox and straight th
451. ywheel NOTE Refer to above b Rebuilding Converter Turbine Assembly A foldout 10 NOTE Do not disassemble the turbine unless the drive gear or turbine hub must be replaced If the converter turbine is damaged replace the assembly A hydraulic press having a minimum capacity of ten tons an adjustable press bed with a 25 inch opening and a pressure gauge to assist in determining the rivet staking load A reworked turbine assembly must be rebalanced 1 Remove ball bearing 6 A foldout 10 if not previously removed 2 Punch mark relationship of lockup clutch hub and turbine gc us FLYWHEEL 81175 Figure 6 3 Removing or installing lockup clutch piston PRESS SLEEVE FLUSH 1 75 4 WITH SURFACEX Md 2 2 1 LLLA T E 6881519 b AFTER SLEEVE IS INSTALLED MAKE SURE THE 210 21815 54 mm DIA OIL PASSAGE HOLES ARE OPEN DIA B MUST BE CONCENTRIC WITH DIAA WITHIN 0 0 102 TIR 123824 Fig 6 4 Rework of flywheel cross section view 3 Using figure 6 5 jas a guide place base plate J 29535 1 on a work bench hole side up 4 Place converter turbine assembly 8 foldout 10 hub 10 side up on top of base plate J 29535 1 Align the sixteen rivets to the sixteen holes in the baseplate Copyright 1983 General Motors Corp REBUILD OF SUBASSEMBLIES BOLT 1 2 13 x 3 1 2 J 29535 LOCKUP CLUTCH HUB CONVERTER TURB INE TURBINE HUB BA

TM 5-4210-227-24&P-3

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TM 5-4210-227-24&amp;P-3

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TM 5-4210-227-24&P-3