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1. 7C 43 Valve Body Disassembly Inspection and Reassembly sese 7C 44 Assembly of Transmission from Major Parts and Units essere 7C 45 Converter Checking Procedure aa a aa u anaq asss tetto 7C 56 Installation of Governor Bushing u 7C 57 SPECIFICATIONS General Specifications u n dtt a ka aS s u 7C 60 DESCRIPTION AND OPERATION DESCRIPTION OF TURBO HYDRA MATIC 350 375B AUTOMATIC TRANSMISSION The Turbo Hydra Matic 350 375B transmission see Fig ure 7C 1 is a fully automatic unit consisting primarily of 3 element hydraulic torque converter and two planetary gear sets Four multiple disc clutches two roller clutches and an intermediate overrun band provide the friction elements required to obtain the desired function of the two planetary gear sets The 3 element torque converter consists of a pump tur bine and a stator assembly The stator is mounted on a one way roller clutch which will allow the stator to turn clock wise but not counterclockwise References to clockwise and counterclockwise are determined by looking toward rear of car 7C 2 1975 BUICK SERVICE MANUAWV a hydramatic 375B transmission is The torque converter is of welded construction and is serviced as a complete assembly The unit is filled with oil and is attached to the engine crankshaft by a flywheel thus always rota
2. Figure 7C 99 RETAINING RING PRESSURE PLATE DIRECT CLUTCH DRUM RETAINING A SPRING RING RETAINER SNAP RING PLIERS 7 168 Figure 7C 103 7C 165 DIRECT CLUTCH PISTON RETURN SPRINGS 17 Figure 7C 100 1 Pitting and flaking 2 Wear 3 Glazing 4 Cracking 5 Charring 6 Chips or metal particles imbedded in lining If a lined drive plate exhibits any of the above conditions replacement is required B Wipe steel plates dry and check for heat discoloration om If the surface is smooth and an even color smear is in DIRECT CLUTCHR dicated the plates should be reused If severe heat spot PISTON discoloration or surface scuffing is indicated the plates d 7 169 must be replaced Figure 7C 104 8 Remove direct clutch piston UIC CO35b 375B TRANSMISSION ring and spring seat by using Tools J 2590 3 J 2590 5 and snap ring pliers See Figure 7C 103 9 Remove spring retainer springs and piston See Figure 7C 104 10 Inspect the return springs Evidence of extreme heat or burning in the area of the clutch may have caused the springs to take a heat set and would justify replacement of the springs 11 Remove direct clutch piston inner and outer seals See Figure 7C 105 OUTER SEAL DIRECT CLUTCH PISTON INNER SEAL 7C 170 Figure 7C 105 12 Remove direct clutch piston center seal See Figure 7C 106 DIRECT CLUTCH DRUM CLUTCH PISTON
3. 8 Remove the alignment arbor 9 Using reamer J 22976 9 and drive rachet Aand ream the governor bore using the following procedure Hand Ream Only a Oil the reamer drill bushing and governor bore b Use 5 10 lbs of feeding force on the reamer See Figure 7 197 After each 10 revolutions remove the reamer and dip it into a cup full of transmission oil This will clean the chips from the reamer and lubricate it See Figure 7C 198 1975 BUICK SERVICE N KNUAL Figure 7C 196 RA TCHET amp SOCKET J 22976 9 Figure 7C 197 d When the reamer reaches the end of the bore continue reaming the bore until the reamer bottoms out on the dowel pin in the case At this point rotate the reamer 10 complete revolutions e Remove the reamer using a clockwise rotation and 5 10 Ibs force upward Pulling the reamer out without rotating it may score the bore causing a leak between the case and the bushing 10 Remove the drill bushing fixture from the case 11 Thoroughly clean the chips from the case visually check the governor feed holes to insure that they are free from chips 12 Install the bushing using the following procedure a Note the two 2 notches at one end of the bushing ww L J 22976 9 BRASS HAMMER TRANSMISSION OIL 7C 247 Figure 7C 198 b Position the notches so that one notch is toward the Figure 7C 200 front of the cas
4. Slips in all ranges 1 Oil level low 1 Add oil slips on take off install pressure gauge 2 Oil pressure 2a Vacuum modulator inoperative b Vacuum modulator valve sticking c Filter assembly plugged or leaks 3 Case 3a Pressure regulator valve stuck b Pump to case gasket damaged or incorrectly installed 4 Forward clutch 4 Cross leaks porosity slipping 5a If burned look for cause b Oil seal rings on pump cover broken or worn Slips 1 2 shift 1 Oil level low 1 Add oil install pressure gauge 2 Oil pressure 2a Vacuum modulator assembly in operative b Modulator valve sticking c Pump pressure regulator valve 3 2 3 accumulator 3 Oil ring damaged or missing www 1 75 TRANSMISSION 7C 9 Condition Possible Cause Correction 4 1 2 accumulator 4 Oil ring missing or damaged case bore damaged 5 Pump to case gasket 5 Mispositioned 6 Case 6 Pososity between channels 7 Intermediate clutch 7 Piston seals missing or damaged clutch plates burned Rough 1 2 shift 1 Oil pressure a Vacuum modulator check for install pressure gauge loose fittings restrictions in line b Modulator valve stuck c Valve body regulator or boost valve stuck d Pump to case gasket off loca tion or damaged 2 Case 2 Porosity between channels 3 1 2 accumulator 3a Oil rings damaged assembly b P
5. unmedicated before installation OUTER SEAL REVERSE CLUTCH PISTON 7C 132 Figure 7C 135 REVERSE CLUTCH PISTON INNER SEAL 7C 133 Figure 7C 137 7 46 3 Do not take a chance on used gaskets and seals use new ones to avoid oil leaks 4 Use care to avoid making nicks or burrs on parts particularly on surfaces where gaskets are used 5 It is extremely important to tighten all parts evenly and in proper sequence to avoid distortion of parts and leak age at gaskets and other joints Use a reliable torque wrench to tighten all bolts and nuts to specified torque and in the specified sequence Installation of Low and Reverse Clutch Piston 1 Install low and reverse clutch piston outer seal See Figure 7C 135 2 Install low and reverse clutch piston center and inner seal See Figure 7C 137 3 Install low and reverse clutch piston assembly with notch in piston installed adjacent to parking pawl See Figure 7C 138 Figure 7C 138 4 Position piston return seat and springs Place snap ring on return seat so that ring may be easily installed when seat is compressed with Tool J 21420 5 Using tool J 21420 1 compress return seat so spring retainer retaining ring may be installed with snap ring pliers See Figure 7C 139 As spring retainer is compressed make certain inner edge of retainer does not hang up on snap ring groove Installing Output Shaft and Reaction Carrier 1 Install output
6. REVERSE REVERSE NEUTRAL amp DRIVE M REVERSE CONVERTER REVERSE DRIVE MANUAL LOW LI MANUAL LOW Ly USED ON 1971 PLATE DETENT REGULATOR LINE EXHAUST REVERSE NEUTRAL A DRIVE v MODULATOR GOVERNOR LINE IMOD S V MODULATOR THRU DETENT VALVE EXHAUST MODULATOR 3 2 DETENT MODULATOR I MODULATOR DETENT GOVERNOR GOVERNOR DRAIN MANUAL LOW 11 MOD S V MODULATOR LOW amp REVERSE THRU DETENT VALVE REVERSE 3 2 DETENT MODULATOR MANUAL LOW L1 5B7C51 Figure 7C 10 Valve Body Spacer Plate 7C 14 1975 BUICK SERVICE TeamBuick com 2 3 DIRECT CLUTCH DRAIN ONVERTE 1 2 INTERMEDIATE CLUTCH REVERSE R N D NEUTRAL AND DRIVE REVERSE WII NEUTRAL AND DRIVE E z EXHAUSY DRAIN UNE i MODULATOR DETENT GOVERNOR MODULATOR VALVE BORE MANUAL LOW 1 DRAIN 3 2 DETENT MODULATOR MODULATOR THRU MLDETENT VAL LOW AND REVERSE Ee 587C52 Figure 7C 11 Identification of Oil Channels in Case Face EXHAUST INTERMEDIATE CLUTCH DIRECT CLUTCH PUMP LIP SEAL DRAIN FORWARD CLUTCH COOLER IN RADIATOR CONVERTER FEED SUCTION COOLER OUT PUMP FROM RADIATOR PRESSURE REVERSE DIRECT CLUTCH OUTER INTERMEDIATE CLUTCH EXHAUST EXHAUST Hu PUMP COVER AND STATOR SHAFT ASSEMBLY 4B7C53 Figure 7C 12 Identification of Oil Channels in Pump Cover and Stator Shaft Face www l eamBuick co 375B
7. STATOR SHAFT INTERMEDIATE 1 2 CLUTCH INTERMEDIATE OVERRUN BAND DIRECT 2 3 CLUTCH OIL PUMPSUCTION INTERMEDIATE O R ROLLER CLUTCH identical to the 350 with the physical difference being an increase in the number of direct clutch plates from four to five This will increase torque capacity High Output Oil Pump To be selected for maximum output from the current production assemblies Close Limit Governor and Modulator To provide more precise pressure control High Capacity Transmission Oil Cooler Same as used with current Upper Series THM 400 transmissions External control connections to the transmission are 1 Manual Linkage To select the desired operating range 2 Engine Vacuum To operate the vacuum modulator 3 Cable Control To operate the detent valve The following shift points are approximate and vary de pending on rear axle ratio In Drive range at minimum throttle the Ist shift will oc cur at 9 14 mph and the 2nd shift at 15 20 mph At maximum throttle the 1st shift will occur at 40 50 mph and the 2nd shift at 68 78 mph The detent valve is activated by a cable that is connected to the accelerator lever assembly When the throttle is half open the valve is actuated causing throttle downshift at speeds below 50 mph When the throttle is fully open the detent valve is actuated causing the transmission to down shift from approximately 3 1 at speeds below 40 mph and 3 2 below
8. 75 mph SUN GEAR amp DRIVE SHELL FORWARD CLUTCH INPUT RING GEAR OUTPUT CARRIER LOW amp REVERSE ROLLER CLUTCH CASE EXTENSION x x EC SPEEDO DRIVE GEAR OUTPUT SHAFT G OVERNOR DRIVEN GEAR VALVE BODY OUTPUT RING GEAR REACTION CARRIER LOW amp REVERSE CLUTCH LOW amp REVERSE CLUTCH SUPPORT 5B7C1 Figure 7C 1 350 375B Automatic Transmission TROUBLE DIAGNosis WWW TRANSMISSION SEQUENCE FOR TURBO HYDRA MATIC 350 375B TRANSMISSION DIAGNOSIS 1 Check and correct oil level 2 Check detent cable adjustment 3 Check and correct vacuum line and fittings 4 Check and correct manual linkage 5 Road test car a Install oil pressure gage b Road test using all selective ranges noting when discre pancies in operation or oil pressure occur c Attempt to isolate the unit or circuit involved in the malfunction d If engine performances indicates an engine tune up is required this should be performed before road testing is completed or transmission correction attempted Poor en gine performance can result in rough shifting or other malfunctions TURBO HYDRA MATIC 350 375B TRANSMISSION CHECKING PROCEDURES Before diagnosis of any transmission complaint is at tempted there must be understanding of oil checking procedure and what appearance the oil should have Many times a transmission malfunction can be traced to low oil level or i
9. 81 INTERMEDIATE CLUTCH PISTON ASSEMBLY FORWARD CLUTCH TO PUMP HUB TEFLON TYPE RINGS 2 PUMP COVER TO DIRECT CLUTCH DRUM NEEDLE THRUST BEARING 017 T SPRING seen DIRECT CLUTCH TO PUMP HUB HOOK TYPE OIL SEAL RINGS 3 PUMP COVER PUMP BODY ATTACHING BOLTS 5 amus 5B7C254 Figure 7C 80 Oil Pump Assembly 7 32 1975 BUICK SERVICE WN CAMBWGl o bypass valve seat check ball and 4 Remove three 3 direct clutch to pump hub hook type oil rings Remove pump cover to direct clutch drum nee dle thrust bearing Inspect the two 2 forward clutch to pump hub teflon oil seal rings but do not remove them unless they are damaged If replacement is necessary use two metal hook type service replacement rings See Figure 7C 80 5 Remove pump cover and stator shaft assembly from pump body See Figure 7C 82 PUMP COVER AND STATOR SHAFT ASSEMBLY PUMP BODY 7C 145 Figure 7C 82 6 Remove pump drive gear and driven gear from pump body Inspect pump gears and cover for wear or scoring See Figure 7C 83 DRIVEN GEAR DRIVE GEAR Figure 7C 83 7 Fill cooler by pass passage with grease and insert Tool spring from pump body See Figure 7C 84 PUMP BODY COOLER BY PASS VALVE J 23134 70 148 Figure 7C 84 8 Remove pump outside diameter to case square cut O ring seal and discard See Figure 7C 86 Figure 7C 86 9 Remove pump body to conver
10. CENTER SEAL 7C 171 Figure 7C 106 13 If bushing replacement is necessary use a Cape Chisel 7C 37 and remove bushing using care not to score inner surface of direct clutch drum See Figure 7C 107 CAPE CHISEL BUSHING Figure 7C 107 14 Install direct clutch bushing using Tool J 23062 4 Drive Handle J 8092 and install 010 below slot in re tainer hub See Figure 7C 108 J 23062 4 DIRECT CLUTCH DRUM 7C 173 Figure 7C 108 Reassembly of Direct Clutch 1 Install direct clutch piston outer seal and inner seal See Figure 7C 105 2 Install direct clutch piston center seal See Figure 7C 106 3 Install the direct clutch piston into housing with the aid 7C 38 1975 BUICK SERVICE MARUAV CAME of a piece of 020 music wire crimped into copper tubing See Figure 7C 109 020 MUSIC WIRE CRIMPED INTO COPPER TUBING PISTON DIRECT CLUTCH HOUSING 70 174 Figure 7C 109 4 Install spring retainer and springs Compress spring retainer and install retaining ring using Tools J 2590 3 and J 2590 5 See Figure 7C 103 5 Lubricate with transmission fluid and install faced plates and steel separator plates starting with a steel plate and alternating steel and faced See Figure 7C 110 6 Install direct clutch pressure plate and retaining ring See Figure 7C 100 7 Install intermediate overrun roller clutch assembly See Figure 7C 112 DIRECT CLUTCH DRUM DIRECT
11. CLUTCH PISTON ASSEMBLY RETAINING RING STEEL PLATES Figure 7C 110 Roller clutch assembly must be assembled with four 4 holes up toward front of transmission 8 Install intermediate clutch overrun outer race See Fig ure 7C 112 When the intermediate overrun clutch outer race is in stalled it should free wheel in the counterclockwise direc tion only 9 Install intermediate overrun clutch retainer and retain ing ring See Figure 7C 112 DISASSEMBLY AND REASSEMBLY OF FORWARD CLUTCH ASSEMBLY NOTE Refer to specifications in rear of this section to determine the required amount of lined and steel clutch STEEL SEPARATOR PLATES FACED PLA TE DIRECT CLUTCH PRESSURE PLATE RETAINING RING 7C 178 Figure 7C 111 Direct Clutch Assembly Exploded View www T eamBuick CG880 758 TRANSMISSION CAUTION IF ROLLER FALLS OUT DURING ASSEMBLY OPERATION REINSTALL ROLLER FROM INSIDE TO OUTSIDE CAGE DIRECTION TO AVOID BENDING SPRING INTERMEDIATE CLUTCH OVERRUN OUTER RACE LOCKS ON CLOCKWISE ROTATION RETAINER RETAINING RING ROLLER CLUTCH ASSEMBLY DIRECT CLUTCH DRUM WITH 4 HOLES AND INTERMEDIATE CLUTCH d TOWARD FRONT OF TRANSMISSION 4B7C176 OVERRUN INNER CAM Figure 7C 112 Intermediate Overrun Roller Clutch Assembly plates to use with specific transmission model and engine combination When replacing piston assembly specific part number must be used
12. Figure 7C 124 Use a new ring and do not overs tress when installing DISASSEMBLY AND REASSEMBLY OF LOW AND REVERSE ROLLER CLUTCH ASSEMBLY Disassembly of Low and Reverse Roller Clutch Assembly Refer to Figure 7C 129 1 Remove low and reverse clutch to sun gear shell thrust washer LOW AND REVERSE CLUTCH SUPPORT ASSEMBLE WITH YELLOW PAINT MARK TOWARD FRONT OF TRANSMISSION ROLLER CLUTCH ASSEMBLY SNAP RING INNER RACE CAGE MUST HAVE 4 EQUALLY SPACED THRUST WASHER IF ROLLER FALLS OUT INSTALL ROLLER 091 LUBE HOLES ON THIS SIDE FROM OUTSIDE IN AS SHOWN TO AVOID BENDING SPRINGS 70202 Figure 7C 129 Low and Reverse Clutch Support and Overrun Roller Clutch Assembly 2 Remove low and reverse overrun clutch inner race www I eamBuliCk CG65g szss TRANSMISSION 7C 43 3 Remove low and reverse roller clutch retaining ring 4 Remove low and reverse roller clutch assembly and visually inspect the rollers for wearing and scoring and check for any springs that may be collapsed Reassembly of Low and Reverse Roller Clutch Assembly 1 Install low and reverse roller clutch assembly to inner race See Figure 7C 130 The inner race should free wheel in the clockwise direction only ROLLER CLUTCH ASSEMBLY 7C 203 Figure 7C 130 2 Install low and reverse overrun roller clutch assembly and inner race into the low and reverse clutch support See Figure 7C 131 Assemble with four 4 holes do
13. be replaced See Figure 7C 78 Piston and Seal are one assembly Installation of Intermediate Clutch 1 2 Accumulator Piston 1 Install intermediate clutch 1 2 accumulator piston as sembly See Figure 7C 78 2 Install intermediate clutch M Wud ana BUICK TRANSMISSION spring See Figure 7C 78 3 Place O ring seal on intermediate clutch 1 2 ac cumulator piston cover and install cover into case See Figure 7C 78 4 Install J 23069 tool and compress intermediate clutch 1 2 accumulator cover and install retaining ring See Fig ure 7C 77 INTERMEDIATE CLUTCH SPRING SEAT RETAINER PUMP COVER TO PUMP BODY BOLTS 5 j 5B7C141 Figure 7C 79 PUMP TO CONVERTER SPRING HUB LIP SEAL yo 24 COOLER BY PASS an VALVE SEAT DRIVEN GEAR DRIVE GEAR PUMP BODY ASSEMBLY PUMP COVER AND STATOR SHAFT ASSEMBLY SQUARE CUT O RING SEAL 7C 31 DISASSEMBLY AND REASSEMBLY OF OIL PUMP ASSEMBLY Disassembly of Oil Pump Assembly 1 Place assembly through hole in bench Remove five 5 pump cover to body attaching bolts See Figure 7C 79 2 Remove intermediate clutch return spring seat retainer with springs and the intermediate clutch piston assembly See Figure 7C 80 3 Remove intermediate clutch piston inner and outer seals See Figure 7C 81 INTERMEDIATE CLUTCH PISTON OUTERSEA a a RUD INTERMEDIATE CLUTCH PISTON INNER SEAL 4B7C143 Figure 7C
14. release parking brake and disconnect the battery 7 20 1975 BUICK SERVICE Ga VALVE BODY B SPACER PLATE VALVE BODY TO SPACER PLATE GASKET 5B7C70 nS Figure 7C 27 Figure 7C 28 2 Disconnect detent cable from accelerator lever or car buretor assembly 3 Raise car and provide support for front and rear NOTE On some models the exhaust crossover pipe may have to be removed 4 Remove the propeller shaft H Series remove upper torque arm transmission end 5 Remove vacuum line from vacuum modulator 6 Being careful not to bend the detent cable remove plastic guide straight up from bracket and slide detent cable out through slot 7 Remove detent cable from detent valve link Do not bend cable at ne pu mes a VA LVE BODY SPACER PLATE mae OTT i Mi VALVE BODY SPACER B ll PLATE TO CASE GASKET Figure 7C 29 8 Support engine at oil pan 9 Assemble transmission to suitable transmission jack 10 Remove transmission mounting pad to crossmember nut 11 Raise transmission and remove crossmember to frame rail bolts Remove crossmember 12 Lower transmission enough to remove cooler lines speedometer cable shift linkage catalytic converter bracket on Series and the filler pipe 13 Remove flywheel cover pan 14 Mark flywheel and converter for reassembly in the same position and remove three converter to flywheel bolts
15. remove the retaining pin spring seat and the detent regulator valve 8 Install Tool J 22269 on direct clutch 2 3 accumulator piston and remove retaining E ring G See Figure 7C 134 9 Remove direct clutch 2 3 accumulator piston and spring G If the teflon piston seal needs replacing the piston assembly will have to be replaced Piston and Seal are one assembly 10 From the next bore down D from the direct clutch accumulator remove the detent actuating lever bracket bolt bracket actuating lever and retaining pin stop spring retainer seat outer spring inner spring washer and the detent valve Use care when handling valve body assembly as valve body sleeve retaining pins may fall out TEFLON OIL SEAL NOT SERVICEABLE or amp M 36 gt 5 25 1 e 32 gt 20 Q WAN aa 14 is 22 17 18 i 9 33 3 30 IP SEP toe dh Ze USED ON KL MODEL ONLY re NYY cm ito 8 9 10 N 2 43 EE tm oo SED 2 3 4 5 6 7 J 1 MANUAL VALVE AND LINK ASSEMBLY 14 1 2 SHIFT VALVE 27 DETENT VALVE 2 PRESSURE REGULATOR VALVE 15 1 2 SHIFT CONTROL VALVE 28 WASHER 3 PRESSURE REGULATOR VALVE SPRING C416 1 2 SHIFT CONTROL VALVE SPRING 29 DETENT VALVE INNER SPRING 4 REVERSE AND MODULATOR BOOST VALVE 17 1 2 SHIFT CONTROL VALVE SLEEVE 30 DETENT VALVE OUTER SPRING 5 INTERMEDIATE BOOST VALVE 18 RETAINING PIN 31 DETENT VALVE OUTER SPRING SEAT 6 BOOST VALVE SLEEVE 19 MANUAL LOW CONTROL VALVE 04 32 DETENT V
16. retainer spring See Figure 7C 61 FOR ILLUSTRATION PURPOSES THE TRANSMISSION HAS 209 LOW AND REVERSE CLUTCH SUPPORT N ERSE ROLLER CLUTCH ASE RETAINER SPRING a M TRANSMISSION CASE LOW AND REVERSE ROLLER CLUTCH CASE RET NG Figure 7C 63 Fi 7C 61 igure 2 Inspect reaction carrier bushing for wear or galling If replacement is necessary proceed as follows Removal of Low and Reverse Clutch Plates a Thread tool J 23062 3 on Drive Handle J 8092 and 1 Remove five 5 or 4 low and reverse clutch faced remove See Figure T6564 plates and five 5 or 4 steel separator plates See Figure b Using Tool J 23062 3 press in new bushing flush to 7 62 010 from inner surface of hub See Figure 7C 64 7c 28 1975 BUICK SERVICE MANVAL camBuick com OUTPUT RING GEAR J 8092 REACTION CARRIER J 23062 3 5B7C124 7 121 7 66 4 Remove output ring gear to case needle bearing See Figure 7C 64 Figure 7C 67 REMOVAL OF OUTPUT RING GEAR AND SHAFT ASSEMBLY AND OUTPUT RING GEAR TO CASE NEEDLE BEARING ASSEMBLY Removal of Output Ring Gear and Shaft Assembly 1 Remove output ring gear and shaft assembly from case See Figure 7C 65 Figure 7C 67 e OUTPUT RING GEAR Figure 7C 65 J 2619 4 ADAPTER 2 Remove reaction carrier to output ring gear needle thrust bearing 3 Remove output ring gear to output shaft snap ring and
17. reverse clutch support retainer spring See Figure 7C 145 LOCATION OF LOW AND REVERSE ROLLER CLUTCH SUPPORT TO CASE RETAINER SPRING Figure 7C 145 3 Install low and reverse clutch support assembly pushing firmly until support assembly is seated past top of low and reverse clutch support retainer spring and retaining ring can be installed See Figure 7C 146 Make certain the splines on inner race of the roller clutch align with splines on reaction carrier 7 48 1975 BUICK SERVICE CQ P OUTPUT CARRIER ASSEMBLY amp Figure 7C 146 4 Install low and reverse clutch support to case retaining ring See Figure 7C 145 Installing Sun Gear Drive Shell Assembly 1 Install low and reverse clutch support inner race to sun gear drive shell thrust washer and install sun gear drive shell assembly See Figure 7C 147 Figure 7C 149 Figure 7C 147 Installing Output Carrier Assembly 1 Install output carrier assembly See Figure 7C 148 2 Install input ring gear to output carrier needle thrust j bearing lip side face down See Figure 7 149 Figure 7C 151 3 Install output carrier to oup WWW L gam Buick COIm 5758 TRANSMISSION 7C 49 Use new snap ring and do not over stress on installing USE PROPER SNAP RING PLIERS See Figure 7C 149 Installing Input Ring Gear 1 Install input ring gear See Figure 7C 151 2 Install forward clutch housing to input ring gear front thrust washer S
18. using screwdriver See Figure 7C 40 SCREWDRIVER EXTENSION HOUSING LIP SEAL 7C 84 Figure 7C 40 Removal of Extension Housing Bushing 1 Remove extension housing bushing using screwdriver to collapse bushing See Figure 7C 41 INSTALL EXTENSION HOUSING BUSHING AND LiP SEAL Installation of Extension Housing Bushing 1 Install extension housing bushing using Drive Handle J 8092 and Bushing Tool J 21424 1 See Figure 7C 42 NOTCH IN EXTENSION HOUSING EXTENSION HOUSING BUSHING J 8092 J 21424 1 EXTENSION HOUSING 7C 86 Figure 7C 42 Installation of Extension Housing Lip Seal 1 Install extension housing lip seal using Installer J 21426 See Figure 7C 43 REMOVAL OF OIL PUMP SCREEN GOVERNOR SCREENS AND CHECK BALLS Removal of Pressure Screen 1 Remove oil pump pressure screen from oil pump pres sure hole in case and clean See Figure 7C 44 2 Remove governor screens from case and clean See Figure 7C 45 www TeamBuick co8B0 3758 TRANSMISSION 7 23 EXTENSION HOUSING LIP SEAL 7C 87 Figure 7C 43 Figure 7C 44 Figure 7C 45 7 24 1975 BUICK SERVICE t from case Remove range selector Te a rb EM le ebd povi rod Removal of Check Balls 1 Remove four check balls from case face REMOVAL OF MANUAL SHAFT INNER LEVER PARKING PAWL AND INTERMEDIATE SERVO PISTON Removal of Range Selector Inner Lever 1 Remove manual c
19. 1 020 MUSIC WIRE CRIMPED INTO COPPER TUBING PISTON FORWARD CLUTCH HOUSING jc 187 Figure 7C 121 3 Install spring retainer and springs Compress spring retainer with an arbor press or ram press See Figure 7C 115 4 Lubricate with transmission fluid and install cushion spring faced plates and steel separator plates starting with the cushion spring and alternating steel and faced See Figure 7C 116 5 Install forward clutch pressure plate and retaining ring Using a feeler gage check clearance between forward clutch pressure plate and faced plate See Figure 7C 122 The specifications for this transmission call for a clearance of no less than 011 and no greater than 082 There are three pressure plates available which are identified by tangs adjacent to the source identification mark See Fig Figure 7C 122 IDENTIFICATION MARKS PLATE IDENTI FICATION THICKNESS MARKS 245 255 NONE 275 285 1 306 316 2 FORWARD CLUTCH PRESSURE PLATE Figure 7C 123 7 42 1975 BUICK SERVICE MANDAN CANA Edel Gef fo drive shell flat rear thrust washer ure 7C 123 These three pressure plates have different thicknesses If the clearance between the forward clutch pressure plate and the faced plate checks out to be less than 011 a thinner pressure plate should be used to have a clearance between 011 and 082 If the clearance checks out to be greater than 082 a thicker press
20. 15 Remove transmission case to engine block bolts 16 Slide transmission rearward and lower it away from car using tool J 21366 to hold converter in place Installation The installation of the transmission is the reverse of re moval except for the following reminder steps 1 Connect converter and flywheel in original position 2 Torque engine to transmission case bolts to 35 Ib ft 3 Torque flywheel to converter bolts to 30 Ib ft 4 Fill transmission with fluid as described in fluid recommendations O Section Maintenance PRELIMINARY INSTRUCTIONS 1 Before starting disassembly of the transmission it should be thoroughly cleaned externally to avoid getting dirt inside 2 Place transmission on a CLEAN work bench and use CLEAN tools during disassembl ide cl a 0359 375B TRANSMISSION 7C 21 space for parts and units removed ou Errem B u IC COT S708 TRANSMISSION 16 21 3 The transmission contains parts which are ground and highly polished therefore parts should be kept separated to avoid nicking and burring surfaces 4 When disassembling transmission carefully inspect all gaskets at times of removal The imprint of parts on both sides of an old gasket will show whether a good seal was obtained A poor imprint indicates a possible source of oil leakage due to gasket condition looseness of bolts or uneven surfaces of parts 5 None of the parts require forcing when disassembling or assembling transmission Use a r
21. ALLATION OF THESE RETAINERS THAT THE CABLE 15 NOT KINKEO OR DAMAGED INSTALL CABLE THRU THROTTLE LEVER HOLE INSTALL RETAINER INTO THROTTLE LEVER HOLE BEING SURE IT 1S SEATED ADJUSTMENT THROTTLE CABLE MUST BE CONNECTED TO CARBURETOR AND THROTTLE LEVER DEPRESS ACCELERATOR PEDAL TO WIDE OPEN THROTTLE POSITION TO ADJUST DETENT CABLE ACCELERATOR PEDAL amp LEVER ASM A SHOWN 5B7C59 Figure 7C 16 Transmission Detent Cable Adjustment A and B Series www T eamBuliCck COd89 3758 TRANSMISSION BOLT 2 10 20 LB FT SNAP LOCK 18 753 DISENGAGED POSITION BRACKET THROTTLE CONTROL CABLE BRACKET VIEW A X SERIES BOLT 6 LB FT b WASHER z S AD 7C 17 SNAP LOCK DISENGAGED POSITION THROTTLE CONTROL CABLE BRACKET H SERIES ATTACH DETENT CABLE TO TRANSMISSION CLIP ENGINE BRACKET AND CARBURETOR ADJUSTMENT 1 INSURE THAT SNAP LOCK BUTTON 15 IN DISENGAGED POSITION CABLE SHOULD BE FREE TO SLIDE THRU SNAP LOCK 2 OPEN CARBURETOR LEVER WIDE OPEN THROTTLE STOP 3 PUSH SNAP LOCK TO ENGAGE POSITION SNAP LOCK FLUSH WITH REST OF CABLE FITTING APPLY OIL BEFORE ASSEMBLY v FITTING MUST HAVE LOCKING TANGS EXPANDED AND LOCKED IN BRACKET ATTACHING HOLE 5B7C17 Figure 7C 17 Detent Cable Adjustment H and X Series REMOVAL OF PROPELLER SHAFT YOKE SEAL 375B ONLY SPEEDOMETER DRIVE GEAR AND GOVERNOR Removal of Propeller Shaft Y
22. ALVE SPRING RETAINER 7 RETAINING PIN df MANUAL LOW CONTROL VALVE SPRING 33 DETENT VALVE STOP B 2 3 SHIFT VALVE 21 PLUG 34 DETENT VALVE ACTUATING LEVER BRACKET 9 2 3 SHIFT VALVE SPRING 22 RETAINING PIN 35 DETENT VALVE ACTUATING LEVER B4 10 2 3 SHIFT CONTROL VALVE 23 DETENT REGULATOR VALVE 36 RETAINING BOLT 11 2 3 SHIFT CONTROL VALVE SPRING p424 DETENT REGULATOR VALVE SPRING SEAT 37 RETAINING PIN 12 2 3 SHIFT CONTROL VALVE SLEEVE 25 DETENT REGULATOR VALVE SPRING 13 RETAINING PIN 26 RETAINING PIN 39 OIL SEAL RING 40 DIRECT CLUTCH 2 3 ACCUMULATOR PISTON 38 DIRECT CLUTCH ACCUMULATOR SPRING G 41 RETAINER RING VALVE BODY ASSEMBLY 5B7C205 Figure 7C 133 Valve Body Assembly DIRECT CLUTCH 2 3 ACCUMULATOR PISTON J 22269 5B7C206 Figure 7C 134 Valve Body inspection 1 Inspect all valves for scoring cracks and free movement in their respective bores 2 Inspect valve body for cracks scored bores intercon nected oil passages and flatness of mounting face 3 Check all springs for distortion or collapsed coils Reassembly of Valve Body 1 Install direct clutch accumulator piston spring and pis ton into valve body 2 Install special tool J 22269 and J 24675 installs piston evenly on direct clutch 2 3 accumulator piston and com press spring and piston and secure with retaining ring See Figure 7C 134 Align piston and oil seal ring when enter ing bore 3 Install the detent valve washer outer spring inner
23. Disassembly of Forward Clutch 1 Remove forward clutch drum to pressure plate retain ing ring Remove forward clutch pressure plate See Figure 7C 113 RETAINING RING FORWARD CLUTCH ASSEMBLY FORWARD CLUTCHI 4 PRESSURE PLATE Figure 7 113 2 Remove forward clutch housing faced plates steel plates and cushion spring See Figure 7C 114 3 Inspect condition of lined and steel plates Do not diagnose a lined drive plate by color 7C 39 A Dry lined plates with compressed air and inspect the lined surfaces for 1 Pitting and flaking 2 Wear 3 Glazing 4 Cracking 5 Charring 6 Chips or metal particles imbedded in lining If a lined drive plate exhibits any of the above conditions replacement is required B Wipe steel plates dry and check for heat discoloration CUSHION SPRING SEPARATOR PLATES 7C 192 Figure 7C 115 7C 40 1975 BUICK SERVICE MANUAV eamBuick com FORWARD CLUTCH PISTON ASSEMBLY FORWARD CLUTCH DRUM INPUT SHAFT RETAINING RING STEEL SEPARATOR PLATE CUSHION SPRING RETAINING RING FACED PLATE FORWARD CLUTCH PRESSURE PLATE 5B7C191 Figure 7C 116 Forward Clutch Assembly Exploded View If the surface is smooth and an even color smear is in dicated the plates should be reused If severe heat spot discoloration or surface scuffing is indicated the plates must be replaced 4 Remove spring retainer and springs b
24. ERVICE MANUAY oamBuick com Condition Possible Cause Correction Harsh 1 2 shift 1 1 2 accumulator la Piston or spring b Accumulator feed hole in valve body plate Slow reverse 1 Valve body la Leaking valve body support hot only plate 2 Shift selector lever 2a Bent or S hook hole off location b S hook bent Detent roller spring hole off location d Manual valve S hook hole off location CAUSES OF IMPROPER VACUUM AT MODULATOR 1 Engine Tune up b Loose vacuum fittings 1 2 PRESSURE c Vacuum operated accessory leak hoses vacuum ad vance etc d Engine exhaust system restricted 2 Vacuum line to modulator a Leak b Loose fitting TRANSMISSION LINE PRESSURE CHECKS c Restricted orifice or incorrect orifice size 1 MINIMUM PSI P N L2 d Carbon build up at modulator vacuum fitting PRR SENE EN e Pinched line 62 M 86 Il check ALTITUDE ABOVE f Grease in pipe no or delayed upshift cold Breuer SEA LEVEL see below O Ft 153 153 239 2 000 153 153 224 4 000 145 147 205 6 000 134 139 191 8 000 124 132 176 10 000 115 125 164 12 000 106 118 151 14 000 98 112 139 STALL CHECK Stall engine at full throttle for no more than 10 seconds in Reverse Drive 12 or L1 HOIST CHECK or Li range Run the engine at 1200 RPM with the modulator vacuum pipe dis connected Lock the brakes at O MPH 5B7C48 Figure 7C 8 www Tl eamBu
25. J 21424 7 and Drive Handle J 8092 tap bushing into shaft to 1 4 inch below top of stator shaft See Figure 7C 91 Extreme care must be taken so bushing is not driven past shoulder 7C 33 J 8092 DRIVE PUMP BODY HANDLE if J 21465 17 Figure 7 89 J 21465 15 J 2619 4 ADAPTER BODY PUMP PUMP COVER AND STATOR SHAFT ASSEMBLY 7C 153 Figure 7C 90 14 If replacement of lower rear stator shaft bushing is required proceed as follows Thread Tool J 21465 15 into stator shaft lower rear bushing Thread Slide Hammer J 2619 into remover Clamp slide hammer into vise Grasp stator shaft and remove bushing See Figure 7C 92 If upper rear stator shaft bushing is required repeat above procedure Using Tool J 23062 2 press upper rear stator shaft bush ing 1 1 32 inch below top surface of oil pump delivery sleeve See Figure 7C 93 Using Tool J 23062 2 press lower rear stator shaft bushing flush to 010 below chamfer on oil pump delivery sleeve 7C 34 1975 BUICK SERVICE MANUAL eamBuick com J 8092 DRIVE HANDLE J 21424 7 PUMP COVER PUMP AND STATOR BODY SHAFT ASSEMBLY 7C 154 Figure 7C 91 J 21465 4 ADAPTER J 2619 4 Pad SLIDE HAMMER PUMP COVER AND STATOR SHAFT ASSEMBLY 5B7C155 Figure 7C 92 Reassembly of Oil Pump Assembly 1 Install pump drive gear and driven gear Drive gear has off set tangs assemble with tang face up to pre
26. NG SPRING Figure 7C 168 3 Install parking pawl shaft retainer plug Drive into case using a 3 8 dia rod until retainer plug is flush to 010 below face of case Stake plug in three 3 places to retain plug in case See Figure 7C 169 Figure 7C 169 4 Install park lock bracket torque bolts to 29 Ib ft See Figure 7C 171 PARK LOCK BRACKET Figure 7C 171 5 Install actuating rod under the park lock bracket and parking pawl See Figure 7C 172 mv am GU X RANGE SELECTOR des Figure 7C 172 Installing Manual Shaft and Range Selector inner Lever 1 If a new manual shaft to case lip seal is necessary use a 7 8 diameter rod and seat flush with case See Figure 7C 173 2 Install manual shaft through case and range selector inner lever 3 Install retaining jam nut on manual shaft Torque jam nut to 30 Ib ft See Figure 7C 174 Install manual shaft to case retainer 7C 53 Figure 7C 173 LEVER TO MANUAL SHAFT NUT Figure 7C 174 Installing Intermediate Servo Piston Check Balls Oil Pump Pressure Screen and Governor Feed Screens 1 Install intermediate servo piston apply pin spring seat See Figure 7C 175 2 Install four 4 check balls into correct transmission case pockets See Figure 7C 176 If number one 1 check ball is omitted or incorrectly placed transmission failure will result due to minimum line pressure If transmission is still in car place check b
27. R STATOR OPERATION DIAGNOSIS 1 The stator assembly freewheels in both directions If the stator roller clutch becomes ineffective the stator assembly freewheels at all times in both directions With this condition the vehicle will tend to have poor accelera tion from a standstill At speeds above 30 35 m p h the vehicle may act normal If poor acceleration problems are noted it should first be determined that the exhaust sys tem is not blocked the engine is in good tune and the transmission is in first Ist gear when starting out If the engine will freely accelerate to high r p m in Neu tral N it can be assumed that the engine and exhaust system are normal Driving the vehicle in Reverse R and checking for poor performance will help determine if the stator is freewheeling at all times 2 The stator assembly remains locked up at all times If the stator assembly remains locked up at all times the engine r p m and vehicle speed will tend to be limited or restricted at high speeds The vehicle performance when accelerating from a standstill will be normal Engine over heating may be noted Visual examination of the converter may reveal a blue color from the overheating that will result Under both conditions or 2 if the converter has been removed from the transmission the stator roller clutch can be checked by inserting a finger into the splined inner race of the roller clutch and trying to turn the race in both di
28. TRANSMISSION 7C 15 EXHAUST EXH AUST PUMP PRESSURE INTERMEDIATE CLUTCH REVERSE COOLER BY PASS VALVE 6 COOLER OUT FROM RADIATOR COOLER IN RE VERSE DIRECT CLUTCH FISCRADIATOR OUTER EXHAUST CON VERTER FEED PUMP LIP SEAL DRAIN 4 FORWARD CLUTCH DIRECT CLUTCH EXHAUST PUMP BODY Aeres Figure 7C 13 Identification of Oil Channels in Pump Body Front Face 5 PUMP BODY TO COVER BOLT HOLES INTERMEDIATE CLUTCH APPLY BREATHER COOLER OUT FROM RADIATOR COOLER IN TO RADIATOR DRAIN 8 PUMP TO CASE BOLT HOLES EXHAUST PUMP SEAL DRAIN EXHAUST INTERMEDIATE NO gU et N Wayna DIRECT CLUTCH REVERSE gt INNER CLUTCH OUTER FORWARD CLUTCH PUMP PRESSURE SUCTION CONVERTER FEED FRONT PUMP COVER CASE FACE ccs Figure 7C 14 Identification of Oi Channels in Pump Cover Rear Face 7 16 1975 BUICK SERVICE www TeamBuick com CONVERTER FEED SUCTI FORWARD CLUTCH PUMP PRESSUSE REVER DIRECT CLUTCH OUTER DRAIN 4 CAST OPEN PORTS 8 PUMP TO CASE BOLE Figure 7C 15 Case Pump Identification of Oil Channels MAINTENANCE AND ADJUSTMENTS DETENT CABLE ADJUSTMENT SEE FIGURES 7C 16 AND 7C 17 ROUTE DETENT CABLE UNDER THROTILE CABLE AS SHOWN gt THROTTLE CABLE APPLY 9985158 OIL BEFORE ASM 8 CAUTION CARE MUST BE TAKEN DURING NST
29. a leak at the rear of the transmission In determining the source of a leak proceed as follows 1 Degrease underside of transmission 2 Road test to get unit at operating temperature 3 Inspect for leak with engine running 4 With engine off check for oil leaks due to the raised oil level caused by drain back Possible Points of Oil Leaks 1 Transmission Oil Pan Leak a Attaching bolts not correctly torqued b Improperly installed or damaged pan gasket c Oil pan gasket mounting face not flat 2 Extension Housing a Attaching bolts not correctly torqued b Rear seal assembly damaged or improperly installed c Square seal extension to case damaged or improperly installed 3 Case Leak a Filler pipe O ring seal damaged or missing misposi tion of filler pipe bracket to engine b Modulator assembly O ring seal damaged or improp erly installed c Detent cable connector ring seal damaged or im properly installed d Governor cover not tight gasket damaged or leak be tween case face and gasket e Speedometer gear O ring damaged f Manual shaft seal damaged or improperly installed g Line pressure tap plug loose 4 Leak at Front of Transmission a Front pump seal leaks 1 Seal lip cut Check converter hub etc 2 Bushing moved and damaged Oil return hole plugged 3 No oil return hole b Front pump attaching bolts loose or bolt washer type seals damaged or missi
30. alls in proper position in spacer plate and gasket and carefully raise into position 7 54 1975 BUICK SERVICE MANVAU CQAMBUICK INTER MEDIATE SERVO PISTON AND SEAL WASHER PIN SPRING SEAT SPRING MUST BE ASSEMBLED AS SHOWN TEFLON OIL SEAL RING Figure 7C 175 Intermediate Servo Assembly Figure 7C 177 Exploded View Figure 7C 178 Figure 7C 176 3 Install oil pump pressure screen in the oil pump pres sure hole in case Ring end of screen must be installed toward case face See Figure 7C 177 Clean before in stalling 4 Install governor screens in the case See Figure 7C 178 Clean before installing Installing Valve Body Detent Roller and Spring Assembly and Filter 1 Install valve body spacer plate to case gasket and valve body spacer plate See Figure 7C 179 2 Install valve body to spacer plate gasket See Figure 7C 180 Figure 7C 179 www I eamBuick CO s758 TRANSMISSION 7C 55 VALVE BODY SPACER PLATE VALVE BODY TO Figure 7C 180 3 Install spacer support plate Torque bolts to 13 Ib ft See Figure 7C 181 Figure 7C 181 4 Connect detent control valve wire to detent valve ac tuating lever See Figure 7C 182 5 Install valve body Connect manual control valve link to range selector inner level Torque bolts in random se quence to 13 Ib ft leaving bolt loose for detent roller and spring assembly See Figure 7C 183 When handling valve
31. and or water The only way transmission oil can be on the vacuum side of the modulator is by a leak in the vacuum diaphragm If oil is found the modulator must be replaced If oil is not found in the vacuum side of the modulator but the trans mission oil level is continually low and external leaks are found there is a possibility that a pin hole leak exists in the diaphragm and the modulator should be replaced 3 Inspection for External Damage a Check for dents or cracks in modulator b Check modulator valve sleeve alignment Roll modula tor on a flat surface to determine if the sleeve is concentric to the modulator can See Figure 7C 6 If the sleeve is bent runout will be visible and modulator must be re placed MODULATOR CAN MODULATOR SLEEVE 7C 47 ROLL MODULATOR ON FLAT SURFACE TO DETERMINE IF THE SLEEVE 15 CONCENTRIC TO THE MODULATOR CAN IF THE SLEEVE IS BENT RUNOUT WILL BE VISIBLE Figure 7C 6 Checking Modulator Sleeve Alignment If the modulator passes the above checks the following items should also be checked as a possible cause of the problem 1 Check freeness of modulator valve in modulator 2 Check freeness of modulator valve in transmission case 3 Check the vacuum line from the manifold to modulator for holes cracks or dents Check the rubber hose connec tions at the modulator and at the intake manifold for leaks Condition Possible Cause Correction No drive in dr
32. awhide or plastic mal let to separate tight fitting cases do not use a hard ham mer 7C 76 Figure 7C 32 Figure 7C 33 REMOVAL OF CONVERTER HOLDING TOOL J 21366 CONVERTER VACUUM MODULATOR Removal of Converter 1 Assemble transmission in Fixture J 8763 Do not over tighten See Figure 7C 32 2 Remove converter Holding Tool J 21366 See Figure 7C 33 3 With transmission in Holding Fixture J 8763 remove torque converter assembly See Figure 7C 35 TORQUE CONVERTER ASSEMBLY 7C 79 Figure 7C 35 Removal of Vacuum Modulator 1 Remove modulator assembly attaching bolt and re tainer See Figure 7C 36 VACUUM MODULATOR VACUUM MODULATOR RETAINER Figure 7C 36 7 22 1975 BUICK SERVICE MANAA Buick com 2 Remove vacuum modulator assembly O ring seal and modulator valve from case See Figure 7C 37 Figure 7C 37 REMOVAL OF EXTENSION HOUSING LIP SEAL AND BUSHING Removal of Extension Housing 1 Remove bolt retainer and speedometer driven gear from side of extension housing and remove four 4 extension housing to case attaching bolts See Figure 7C 38 NOTE Remove catalytic converter studs on A B Series Figure 7C 38 Removal of Extension Housing Seal 1 Remove extension housing to case oil seal See Figure 7C 39 EXTENSION HOUSING TO CASE OIL SEAL 7C 83 Figure 7C 39 Removal of Extension Housing Lip Seal 1 Remove extension housing lip seal
33. body assembly do not touch sleeves as retainer pins will fall into transmission 6 Install detent roller and spring assembly to valve body See Figure 7C 184 7 Install filter assembly gasket and filter See Figure 7C M VALVE BODY ASSEMBLY DETENT CONTROL VALVE LINK 7C 232 Figure 7C 182 MANUAL CONTROL VALVE Figure 7C 183 185 Install filter and gasket exactly as shown Always replace filter when foreign material is found to be present Installing Oil Pan Governor and Modulator Valve l Install new bottom pan gasket and bottom pan See Figure 7C 186 2 Install governor assembly cover and seal and retainer wire See Figure 7C 188 Use extreme care not to damage cover If cover is damaged it must be replaced 3 Install vacuum modulator valve and modulator See Figure 7C 189 Lubricate O ring seal to prevent dam age install retaining clip and torque bolt to 12 Ib ft 7 56 1975 BUICK SERVICE MANUAL cambuick com 4B 7C67 Fiaure 7C 185 Figure 7C 189 CONVERTER CHECKING PROCEDURE Check Converter For Leaks as Follows 1 Install tool J 21369 and tighten See Figure 7C 190 2 Fill converter with air 80 psi 3 Submerge in water and check for leaks Check Converter End Clearance as Follows 1 Install tool J 21371 2 and tighten brass nut See Figure 7C 191 2 Install Tool J 21371 3 and tighten hex nut See Figure 7C 192 Figure 7C 186 3 Install dial ind
34. diate i Low and Clutch Reverse Clutch Driven Plate B TIGHTENING SPECIFICATIONS Thread Torque Location Size Lbs Ft Oil Pan to Transmission 5 16 18 13 Pump Assembly to Transmission 5 16 18 20 Vacuum Modulator Retainer to 5 16 18 12 Valve Body Assembly to 5 16 18 13 Oil Channel Support Plate to 5 16 18 13 Pump Body to Pump 5 16 18 15 Parking Lock Bracket to 5 16 18 29 Extension Housing to 3 8 16 35 Inside Shift Nutaz cose ee dde Ea e I aces te Y Near eere 3 8 16 30 External Test Plugs to 1 8 27 8 5B7C256 Figure 7C 203
35. discard Remove output ring gear from output shaft See Figure 7C 66 Figure 7C 69 SLIDE HAMMER J 23062 7 Pt od 5 Inspect output shaft bushing fgi Wwear of UICK COkEb 3758 TRANSMISSION 7 29 replacement is necessary proceed as follows a Assemble J 9534 01 into Adapter J 2619 4 and assem 2 Remove low and reverse clutch piston assembly Aid ble to Slide Hammer J 2619 Thread assembly into bush removal with the use of compressed air in passage shown ing Clamp slide hammer into vise grasp output shaft and See Figure 7C 73 remove bushing See Figure 7C 69 b Using Tool J 23062 7 assembled into Drive Handle J 8092 press in new bushing 140 below end surface of shaft See Figure 7C 70 l APPLY AIR PRESSURE 8092 HERE TO REMOVE LOW DRIVE HANDLE L amp REVERSE CLUTCH PIS J 23062 7 OUTPUT Figure 7C 73 Removal of Low and Reverse Clutch Piston Seals Figure 7C 70 1 Remove low and reverse clutch piston outer seal REMOVAL OF LOW AND REVERSE CLUTCH 2 Remove low and reverse clutch piston center and inner PISTON AND CASE BUSHING i Removal of Low and Reverse Clutch Piston 1 Using Tool J 21420 1 compress low and reverse clutch piston spring retainer and remove piston retaining ring and spring retainer with springs See Figure 7C 71 Figure 7 74 Removal and Installation of Case Bushing 1 Inspect case bushing for nicks scoring or excessive wear If damaged remove as follows Assemble To
36. e and the other is toward the bottom of the case See Figure 7C 199 NOTCHES BUSHING Figure 7C 199 c Use J 22976 3 alignment arbor and bushing installer to drive the bushing into the case See Figure 7C 200 A brass hammer should be used to strike the hardened steel bush ing installer tool d Drive the bushing until it is flush with the top of the bore and seated properly in the case See Figure 7C 201 13 Oil a new governor and insert it into the installed bushing The governor should spin freely If slight honing on the bushing is necessary use crocus or fine emery cloth and move in a circular one way direction only YEAR fa SHIFT BUILT E 1 PRODUCTIO Je N DAY BUILT Transmission Identification Number and Car Serial Number A production day and shift built number transmission Figure 7C 202 MODEL IDENTIFICATION 5B7C257 7 60 1975 BUICK SERVICE MHAE B awe Tp in each transmission they 2000 PUR een POSITI is i n lecting replacement parts as listed in the master parts list The model number and day built model and model year are stamped on the governor cover number should always be furnished on product reports See Figure 7C 202 Since the production day built number warranty document forms and all correspondence with and model number furnishes the key to construction and factory concerning a particular transmission SPECIFICATIONS TURBO HYDRA MATIC 350 3758 AUTOMATIC TRANSMISSION Interme
37. e input ring gear See Figure 7C 57 Figure 7C 57 3 Inspect bushing for wear or galling If replacement is necessary proceed as follows a Thread Tool J 23062 5 on Drive Handle J 8092 and remove bushing from ring gear See Figure 7C 58 b Using Tool J 23062 5 press in new bushing 050 to 060 from inner surface of hub See Figure 7C 58 J 8092 J 23062 5 INPUT RING GEAR 7C 111 Figure 7C 58 Removal of Output Carrier Assembly 1 Remove input ring gear to output carrier needle thrust bearing 2 Remove output carrier to output shaft snap ring and discard See Figure 7C 59 Figure 7C 59 3 Remove output carrier assembly REMOVAL OF SUN GEAR DRIVE SHELL LOW AND REVERSE CLUTCH SUPPORT ASSEMBLY LOW AND REVERSE CLUTCH PLATES AND REACTION CARRIER Removal of Sun Gear Drive Shell Assembly 1 Remove sun gear drive shell assembly See Figure 7C 60 Figure 7C 60 Removal of Low and Reverse Clutch Support Figure 7C 62 Assembly 1 Remove low and reverse roller clutch support to case Removal of Reaction Carrier Assembly ining ring i 61 1 Figure IC 1 Remove reaction carrier assembly from output ring 2 Grasp output shaft and pull up until low and reverse gear and shaft assembly See Figure 7C 63 roller clutch and support assembly clear low and reverse clutch support retainer spring and remove support assem bly 3 Remove low and reverse clutch support
38. ee Figure 7C 151 Washer has three 3 tangs Installing Direct and Forward Clutch Assemblies 1 Install direct clutch drum to forward clutch housing needle roller bearing See Figure 7C 152 DIRECT CLUTCH DRUM TO FORWARD CLUTCH HOUSING NEEDLE ROLLER BEARING Figure 7C 152 2 Install direct clutch assembly to forward clutch assem bly Install assemblies into case making certain forward clutch faced plates are positioned over input ring gear and the tangs on direct clutch housing are installed into slots on the sun gear drive shell See Figure 7C 153 Installing Intermediate Clutch Overrun Brake Band 1 Install intermediate clutch overrun brake band See Figure 7C 154 Figure 7C 154 Installing Intermediate Clutch Pressure Plate Clutch Plates and Cushion Spring NOTE Refer to specifications in rear of this section to determine the required amount of lined and steel clutch Figure 7C 153 Figure 7C 156 7 50 1975 BUICK SERVICE MANWAW CAM ka Ke down on pump cover hub Before installation apply petroleum jelly to both sides of plates to use with specific transmission model and engine shim and bearing See Figure 7C 159 When replacing piston assembly specific part number must be used 1 Install intermediate clutch pressure plate See Figure 7C 156 2 and install lined and steel intermediate clutch plates starting with a lined plate and alternating steel and lined See Fi
39. gure 7C 157 NEEDLE THRUST BEARING 017 SHIM Figure 7C 159 2 Install new pump assembly to case gasket See Figure 7C 160 Before installing pump lubricate case bore Figure 7C 157 3 Install intermediate clutch cushion spring See Figure 7C 158 Figure 7C 160 3 Install guide pins into case Install pump assembly into case remove guide pins and install pump to case bolts Using new washer type seals tighten alternately to 20 Ib 5B7C103 ft torque See Figure 7C 161 Figure 7C 158 4 If input shaft cannot be rotated as the pump is being pulled into place the direct and forward clutch housings Installing Oil Pump Assembly have not been properly installed to index the faced plates with their respective parts This condition must be cor 1 Install original amount of 017 shims and needle rected before the pump is pulled into place BuUICK COssd 375B TRANSMISSION 7 51 5 Checking direct clutch to oil pump clearance attach slide hammer bolt to threaded hole in oil pump See Figure 7C 162 With flat of hand on end of input shaft move shaft rearward Install Dial Indicator Set J 8001 on rod and O dial indicator on end of input shaft Push on end of output shaft to move shaft forward the reading obtained should be between 030 and 079 If the reading is incor rect remove pump assembly and install zero one or two 017 shims to obtain correct reading See Figure 7C 159 Installing Speedome
40. icator set at O WWW Team Bu ick COITU TRANSMISSION 7C 57 J 21371 2 Figure 7C 191 4 Loosen hex nut See Figure 7C 192 When nut is fully loosened the reading obtained on the dial indicator will be converter end clearance If clearance is 050 or over and the oil has the appearance of having been mixed with aluminum paint replace the converter Install Converter See Figure 7C 193 Install Converter Holding Tool J 21366 INSTALLATION OF GOVERNOR BUSHING jj 1 Remove transmission from car 2 Remove the output shaft valve body support plate and governor from the case y d DIAL INDICATOR SET J 21371 3 Figure 7C 192 TORQUE CONVERTER B ASSEMBLY Figure 7C 193 3 Assemble transmission case in fixture J 8763 and mount in a vise See Figure 7C 194 4 Clean off excess stock from the governor o ring seal to case mating surface See Figure 7C 195 5 Loosely bolt the drill bushing fixture J 22976 1 to the case 6 Place the alignment arbor J 22976 3 into the drill bush ing fixture and down into the governor bore until it bot toms on the dowel pin See Figure 7C 196 7 Torque the bolts on the drill bushing fixture 8 12 Ib ft Do not over torque and strip the threads The alignment arbor should be able to rotate freely after 7C 58 Figure 7C 195 the bolts are properly torqued If the alignment arbor cannot be rotated by hand recheck the work performed in step 4
41. ick com 350 375B TRANSMISSION 7C 13 EXHAUST DETENT EXHAUST EXHAUST 11 2 INTERMEDIATE CLUTCH GOVERNOR low DETENT REGULATOR N DETENT R N D REVERSE NEUTRAL amp DRIVE M M MANUALLOW 12 3 DIRECT CiUTCE Ty VALVE BORE EXH AUST LOCATIONS MANUALLOW DETENT REGULATOR REVERSE 2 3 ACCUMULATOR AND LOW MANUAL LOW CONTROL VALVE 1 21 INTERMEDIATE CLUTCH REVERSE DRAIN i N gt p DETENT DRIVE ou EXHAUST Rn 1 2 SHIFT VALVE i MM LINE tow 3 2 DETENT EXHAUST MODULATOR 3 2 DETENT MODULATOR MODULATOR of MOD S V MODULATOR THRU DETENT VALVE p 2 3 SHIFT VALVE MOD S V MODULATOR THRU DETENT VALVE DRIVE EXHAUST 11 2 INTERMEDIA YE CLUTCH MODULATOR GOVERNC SUCTION INTERMEDIATE 12 PRESSURE UN 7 REGULATOR MANUAL LOW L1 J HA UST MANUAL VALVE SUCTION REVERSE 12 3 DIRECT CLUTCH R N D REVERSE NEUTRAL AND DRIVE MANUAL LOW L1 Boze CONVERTER REVERSE DRIVE Figure 7C 9 Identification of Oil Channels in Valve Body NOTE 24 BOLTHOLES MARKED WITH GOVERNOR 8 1 MODULATOR THRU DETENT VALVE 2 3 DIRECT CLUTCH 2 3 DIRECT CLUTCH DRIVE 1 2 INTERMEDIATE CLUTCH SUCTION LINE A 1 2 INTERMEDIATE CLUTCH 2 3 DIRECT CLUTCH am LINE 1 2 INTERMEDIATE CLUTCH ii CLUTCH REVERSE NEUTRAL amp DRIVE INE LINE I x
42. ine or fittings leaking M 3 Control valve assembly 3a Valve body gaskets leaking damaged incorrectly in stalled b Detent valve train stuck c 1 2 valve stuck 4 Case assembly 4 Porosity www leamBuick com 350 375B TRANSMISSION 7C 7 Condition Possible Cause Correction M MM M e First speed only no 1 Governor assembly la Governor valve sticking 1 2 shift b Driven gear loose damaged or worn check for pin in case and length of pin showing also check output shaft drive gear for nicks or rough finish if driven gear shows damage 2 Control valve assembly 2a 1 2 shift valve train stuck closed b Governor feed channels blocked c Valve body gaskets leaking damaged incorrectly installed 3 Case 3a Porosity between channels b Governor feed channel blocked governor bore scored or worn allowing cross pres sure leak 4 Intermediate clutch 4a Clutch piston seals missing improperly assembled cut b Intermediate roller clutch Broken spring or damaged cage First and second speeds 1 Control valve assembly la 2 3 shift train stuck only no 2 3 shift b Valve body gaskets leaking damaged incorrectly installed 2 Direct clutch 2a Pump hub direct clutch oil seal rings broken missing b Clutch piston seals missing improperly assembled cut piston ball chec
43. irect clutch la Direct clutch bore undersize or piston oversize b Direct clutch feed hole shy small chamber Second gear start or 1 Intermediate clutch la Wrong number of clutch plates slips second gear only or wrong piston Locks up in reverse 1 Forward clutch la Bore undersize or piston usually hot only oversize 2 Direct clutch 2 Direct clutch feeding forward clutch thru stator shaft check stator shaft index Locks in reverse from Parking pawl la Parking pawl staying in due to park to reverse only a burr on leading edge ee Cold morning reverse no 1 Pressure regulator la Remove and repair drive till engine warms bore or sleeve tight up ee Shifts cold but not 1 Governor assembly la Nylon gear roll pin shy warm drive but has 1 Low reverse roller la Low reverse roller clutch manual low clutch installed backwards No 1 2 shift makes 1 3 1 Intermediate roller la Intermediate roller clutch shift and 3 1 shift clutch not locking but has all shifts 3 e lt Governor nylon gear 1 Case pin la Governor case pin missing stripped 360 2 Output shaft 2a Output shaft rough or worn C P G D210190 G A Governor gear stripped 1 Governor sizing in la Repair or replace as necessary one side bore Slow reverse 1 Low oil level 1 Adjust oil level cold only 7C 12 1975 BUICK S
44. iston stuck c Broken or missing spring d Bore damaged e Check accumulator feed hole in valve body plate Slips 2 3 shift 1 Oil level low 1 Add oil install pressure gauge 2 Oil pressure low 2a Modulator assembly b Modulator valve c Pump pressure regulator valve or boost valve pump to case gasket off location 3 Case 3 Porosity 4 Direct clutch 4a Piston seals leaking or ball check leak Rough 2 3 shift 1 Oil pressure high a Vacuum leak install pressure gauge b Modulator valve sticking c Valve body pressure regu lator or boost valve in operative 2 2 3 accumulator assembly 2a 2 3 accumulator spring missing broken b Accumulator piston stuck No engine braking l Intermediate servo and la Servo or accumulator oil rings L2 2nd gear 2 3 accumulator or bores leaking b Servo piston stuck 7 10 1975 BUICK SERVICE eamBuick com Condition Possible Cause Correction 2 Intermediate overrun 2 Intermediate overrun band broken band burned check for cause 3 Oil pressure low 3 Pressure regulator and or boost valve stuck No engine braking 1 Manual low control 1 Stuck L 1 Ist gear valve assembly 2 Oil pressure low 2 Pressure regulator and or boost valve stuck 3 Low and reverse clutch 3 Piston inner seal damaged or missing No part throttle downshift 1 Oil pressure a Vacuu
45. ive range 1 Low oil level install pressure gauge Correct level check for exter nal leaks or vacuum modulator leaking diaphragm will evacuate oil from unit 7C 6 1975 BUICK service AWWW T eamBuick com Possible Cause Correction 2 Manual linkage 2 See Section 7E adjustment 3 Low oil pressure 3a Filter assembly blocked b Pump assembly pressure regu lator pump drive gear tangs damaged by converter c Case porosity in intake bore 4 Control valve assembly 4 Manual valve disconnected from inner lever 5 Forward clutch 5a Forward clutch does not apply piston cracked seals mis sing damaged clutch plates burned b Pump feed circuit to forward clutch oil seal rings mis sing or broken on pump cover leak in feed cir cuits pump to case gasket mispositioned or damaged Clutch drum ball check stuck or missing 6 Roller clutch assembly 6 Broken spring or damaged cage Oil pressure high or low 1 High oil pressure la Vacuum line or fittings leaking b vacuum modulator c Modulator valve d Pressure regulator e Oil pump 2 Low oil pressure 2a Vacuum line or fittings ob structed b Vacuum modulator c Modulator valve d Pressure regulator e Governor f Oil pump 1 2 shift full throt tle only 1 Detent valve 1 Sticking or linkage misadjusted 2 Vacuum leak 2 Vacuum l
46. k stuck or missing eee Drive in Neutral 1 Manual linkage 1 Misadjusted 2 Forward clutch 2 Clutch does noi release this 7 condition will also cause No T aai Reverse No motion in Reverse 1 Low oil level 1 Add oil or slips in Reverse I install pressure gauge 2 Manual linkage 2 Misadjusted Refer to Group 7E a Modulator valve stuck b Modulator and reverse boost valve stuck c Pump hub direct clutch oil seal rings broken missing d Direct clutch piston seal cut or missing e Low and reverse clutch piston seal cut or missing f No 1 check ball missing 3 Oil pressure 3 7 8 1975 BUICK SERVICE ww TeamBuick com Condition Possible Cause Correction 4 Control valve as 4a Valve body gaskets leaking sembly damaged incorrectly in stalled other malfunctions may also be indicated b 2 3 valve train stuck in up shifted position This will also cause 1 3 upshift in drive range c 1 2 valve train stuck in up shifted position 5 Intermediate servo 5 Piston or pin stuck so interme diate overrun band is applied eee 6 Low and reverse 6 Piston out or seal damaged or clutch missing 7 Direct clutch 7a Outer seal damaged or missing b Clutch plates burned may be caused by stuck ball check in piston 8 Forward clutch 8 Clutch does not release will also cause Drive in Neutral
47. m modulator assembly install pressure modulator valve pressure gauge regulator valve train other malfunctions may also be noticed 2 Detent valve and 2 Sticks or disconnected or broken linkage 3 2 3 shift valve 3 Stuck No detent downshifts 1 Control valve assembly 1 2 3 valve stuck 2 Detent valve and 2 Sticks or disconnected or broken linkage Low or high shift points 1 Oil pressure a Engine vacuum check at trans install pressure gauge mission end of the modu lator pipe b Vacuum modulator assembly vacuum line connections at engine and transmission modulator valve pressure regulator valve train 2 Governor 2a Valve sticking b Feed holes restricted or leak ing pipes damaged or mis positioned c Feed line plugged 3 Detent valve and 3 Stuck open Will cause late linkage shifts 4 Control valve assembly 4a 2 3 valve train sticking b 1 2 shift valve train sticking 5 Case 5 Pososity www amp 75 TRANSMISSION 7 11 Condition Possible Cause Correction Won t hold in Park 1 Manual linkage 1 Misadjusted 2 Internal linkage 2a Parking brake lever and actuator assembly Check for chamfer on actuator rod sleeve b Parking pawl broken or in operative Locks up in manual low 1 Converter pressure la Check stator shaft index usually hot only leaking into direct clutch thru stator shaft 2 D
48. mproper reading of dipstick Due to the transmis sion fluid that is now being used it may appear to be darker and have a stronger odor This is normal and not a positive sign of required maintenance or transmission failure Also when the dipstick is removed it should be noted whether the oil is devoid of air bubbles or not Oil with air bubbles gives an indication of an air leak in the suction lines which can cause erratic operation and slippage Wa ter in the oil imparts a milky pink cast to the oil and can cause spewing EXTERNAL OIL LEAKS Determining Source of Oil Leak Before attempting to correct an oil leak the actual source of the leak must be determined In many cases the source of the leak can be deceiving due to wind flow around the engine and transmission The suspected area should be wiped clean of all oil before inspecting for the source of the leak Red dye is used in the transmission oil at the assembly plant and will indicate if the oil leak is from the transmission The use of a Black Light to locate the point at which the oil is leaking is helpful Comparing the oil from the leak to that on the engine or transmission dipstick when viewed by black light will determine the source of the leak engine or transmission Oil leaks around the engine and transmission are generally carried toward the rear of the car by air stream For example a transmission oil filler tube to case leak will sometimes appear as
49. n good lines up with the outer gage line See Figure If the modulator bellows in question is good both modula tor assemblies will be within the outer gage lines as the assemblies are slowly brought together See Figure 7C 5 2 Vacuum Diaphragm Leak Check Turn modulator so vacuum line stem points downward If transmission oil comes out the vacuum diaphragm is bad Gasoline and or water vapor may settle in the vacuum side of the modulator If this is found WITHOUT the presence of oil the modulator MUST NOT BE CHANGED www eamBulick cor MODULATOR PART NUMBER IS LOCATED ON BACK SIDE THE ASSEMBLY COMPARISO GAUGE HOLD MODULATORS IN A HORIZONTAL POSITION AS SHOWN BRING THEM SLOWLY TOGETHER UNDER PRESSURE 7C 43 Figure 7C 3 Holding Modulator in Horizontal Position KNOWN GOOD MODULATOR MODULATOR IN QUESTION MODULATOR BELLOWS BAD 70 44 Figure 7C 4 Modulator Bellows Bad OUTER GAUGE LINES SCC MODULATOR BELLOWS GOOD 7C 45 Figure 7C 5 Modulator Bellows Good Check solution that comes out of the modulator for evi TURBO HYDRA MATIC 350 375B TROUBLE DIAGNOSIS CHART Refer to section at end of Diagnosis Chart dealing with causes of improper vacuum at modulator 50 375B TRANSMISSION 7C 5 dence of lubricity If the solution does not have the feel of oiliness it can be assumed the solution is a mixture of gas
50. ng c Front pump housing O ring damaged or cut d Converter leak in weld area e Porous casting pump 5 Oil Comes Out Vent Pipe a Transmission over filled b Water in oil c Foreign material between pump and case or between pump cover and body d Case porous near converter bosses Front pump cover or housing oil channels shy or stock near breather e Pump to case gasket mis positioned 7 4 1975 BUICK SERVICE kon DIAGNOSIS PROCEDURE Case Porosity Repair Turbo Hydra Matic 350 375B transmission external oil leaks caused by case porosity can be successfully repaired with the transmission in the car by using the following recommended procedures 1 Road test and bring the transmission to operating tem perature approximately 190 degrees F 2 Raise car on a hoist or jack stand engine running and locate source of oil leak Check for oil leaks in Low Drive and Reverse 3 Shut engine off and thoroughly clean area to be repaired with a suitable cleaning solvent and a brush air dry A clean dry soldering acid brush can be used to clean the area and also to apply the epoxy cement or equivalent 4 Using instructions of the manufacturer mix a sufficient amount of epoxy or equivalent to make the repair Make certain the area to be repaired is fully covered 5 Allow cement to cure for 3 hours before starting engine 6 Road test and check for leaks CONVERTE
51. oke Seal 375B Only Remove propeller shaft yoke seal using Tool J 23103 and screwdriver See Figure 7C 18 TAP HERE Figure 7C 18 375B Transmission Removal and Installation of Speedometer Drive Gear Removal 1 Depress retaining clip and remove from output shaft Installation l Align slot in speedometer drive gear with retaining clip and install See Figure 7C 19 SPEEDOMETER DRIVE GEAR OUTPUT SHAFT RETAINING CLIP Figure 7C 19 7c 18 1975 Buick service eamBuick com Removal of Governor 1 Remove governor cover retainer wire with a screw driver See Figure 7C 20 Figure 7C 20 2 Remove governor cover and O ring seal from case Aid removal of cover with screwdriver Use extreme care not to damage cover If cover is damaged it must be re placed Remove O ring seal from governor cover and replace See Figure 7C 21 Figure 7C 21 3 Withdraw governor assembly from case See Figure 7C 22 Figure 7C 22 Check governor bore and governor sleeve for scoring Refer to 400 section for governor overhaul procedures MAINTENANCE Draining Oil Pan and Replacing Filter Assembly With transmission in the car 1 Raise car on hoist or place on jack stands and provide container to collect draining fluid Care should be taken if transmission is hot 2 Remove oil pan and gasket Discard gasket 3 Drain fluid from oil pan Clean pan with solvent and dry tho
52. ol J 23062 1 on Drive Handle J 8092 and remove bushing See Figure 7 71 Figure 7C 75 7 30 1975 BUICK SERVICE MANUAL T eam and remove retaining ring See Figure 7C 75 2 Using Tool J 23062 1 and Drive Handle J 8092 press bushing to 195 below chamfered edge of case Make certain split on bushing is opposite notch in case See Figure 7C 76 J 8092 DRIVE HANDLE J 23062 1 Figure 7C 76 REMOVAL AND INSTALLATION OF INTERMEDIATE CLUTCH 1 2 ACCUMULATOR Re moval and installation of intermediate clutch 1 2 ac cumulator can be done without removal of transmission from car Removal of Intermediate Clutch 1 2 Accumulator Piston 1 Install Tool J 23069 to compress intermediate clutch Figure 7C 77 INTERMEDIATE CLUTCH ACCUMULATOR COVER COMPRESSOR J 23069 Figure 7C 77 2 Remove intermediate clutch 1 2 accumulator piston cover and ring seal from case See Figure 7C 78 TEFLON OIL INTERMEDIATE CLUTCH T sS 1 2 ACCUMULATOR PISTON A ASSEMBLY RETAINING RII Figure 7C 78 Intermediate Clutch 1 2 Accumulator 3 Remove intermediate clutch 1 2 accumulator piston spring See Figure 7C 78 4 Remove intermediate clutch 1 2 accumulator piston assembly Inspect the inner and outer teflon oil seal rings for wearing or scoring DO NOT REMOVE THESE TWO RINGS UNLESS THEY ARE DAMAGED If replacement of one or the other of the two rings is neces sary The piston assembly will have to
53. on Housing Bushing and Lip Seal sees 7C 22 Removal of Oil Pump Screen Governor Screen and Check Balls 7C 23 Removal of Manual Shaft Inner Lever Parking Pawl and Intermediate Servo Piston 7C 24 Removal of Pump Assembly Cushion Spring Intermediate Clutch Plates and Overrun Brake PET ERN 7C 25 Removal of Direct and Forward Clutch Assemblies Input Ring Gear and Output Carrier 7 25 Removal of Sungear Shell Low and Reverse Clutch Support Assembly Low and Reverse Clutch Plates and Reaction Carrier ie dete oit bd dedecus 7C 26 Removal of Output Ring Gear and Shaft Assembly and Output Ring Gear to Case Needle Bearing Assembly lan ns eee ieri i EE Ur Re er TEETH 7 28 Removal of Low and Reverse Clutch Piston and Case Bushing 7 29 Removal and Installation of Intermediate Clutch Accumulator 7 30 Disassembly and Reassembly of Oil Pump Assemblly c ssscscssccscssesesesessscsesesssesceresseeees 7 31 Disassembly and Reassembly of Direct Clutch tette 7C 35 Disassembly and Reassembly of Forward Clutch Assembly eese 7C 38 Disassembly and Reassembly of Sungear to Drive Shell sss 7C 42 Disassembly and Reassembly of Low and Reverse Roller Clutch Assembly
54. ontrol valve link retainer from range selector inner lever 2 Remove manual shaft to case retainer with screwdriver See Figure 7C 47 3 Remove jam nut holding range selector inner lever to manual shaft Figure 7C 48 5 Remove manual shaft to case lip seal if necessary See Figure 7C 48 6 Remove parking lock bracket 7 Remove parking pawl shaft retaining plug stake marks Remove retaining plug parking pawl shaft parking pawl and disengaging spring Se Figure 7C 49 inate i DISENGAGING SPRING RETAINING PLUG Figure 7C 49 B Removal of Intermediate Servo Piston 1 Remove intermediate servo piston washer spring seat and apply pin See Figure 7C 50 2 If the piston seal needs replacing the piston assembly will have to be replaced This is due to a plastic grooved piston that is not serviceable Piston and Seal are one assembly NTERMEDIATE SERVO PISTON Figure 7C 50 REMOVAL OF PUMP ASSEMBLA EUEuibK AM BUICK COM TRANSMISSION 7 25 SPRING INTERMEDIATE CLUTCH PLATES AND OVERRUN BRAKE BAND If the surface is smooth and an even color smear is in dicated the plates should be reused If severe heat spot Removal of Oil Pump Assembly discoloration or surface scuffing is indicated the plates 1 Remove eight 8 pump attaching bolts with washer must be replaced type seals Discard washer type seals 2 Install two 2 threaded slide hammers J 7004 into th
55. readed holes in pump body Tighten jam nuts and remove pump assembly from case See Figure 7C 53 Figure 7C 54 4 Remove intermediate clutch pressure plate 3 Remove intermediate overrun brake band See Figure 7C 55 Figure 7C 53 3 Remove pump assembly to case gasket and discard Removal of Intermediate Clutch Cushion Spring Intermediate Clutch Plates and Intermediate Overrun Brake Band 1 Remove intermediate clutch cushion spring 2 Remove three 3 or 2 intermediate clutch faced plates and three 3 or 2 steel separator plates See Figure 3 Inspect condition of the lined and steel plates Do not diagnose a lined drive plate by color A Dry lined plates with compressed air and inspect the lined surfaces for 1 Pitting and flaking 2 Wear 3 Glazing Figure 7C 55 4 Cracking REMOVAL OF DIRECT AND FORWARD CLUTCH 5 Charring ASSEMBLIES INPUT RING GEAR AND 6 Chips or metal particles imbedded in lining OUTPUT CARRIER Ifa lined drive plate exhibits any of the above conditions Removal of Direct and Forward Clutch Assemblies replacement is required 1 Remove direct and forward clutch assemblies from B Wipe steel plates dry and check for heat discoloration case See Figure 7C 56 7 26 1975 BUICK SERVICE MANUAV CAMBUICK Figure 7C 56 Removal of Input Ring Gear 1 Remove forward clutch housing to input ring gear front thrust washer Inspect for excessive wear or scoring 2 Remov
56. rections The inner race should turn freely in the clock wise direction but not turn or be very difficult to turn in the counterclockwise direction NOTE Do not use such items as the pump cover or stator shaft to turn the race as the results may be mislead ing failed vacuum modulator can cause one or more of the following complaints 1 Harsh upshifts and downshifts 2 Delayed upshifts 3 Soft upshifts and downshifts 4 Slips in low drive and reverse 5 Transmission overheating 6 Engine burning transmission oil If any one of the above complaints are encountered the modulator must be checked The vacuum modulator see Figure 7C 2 has three areas to be checked If any one of the three 3 areas fail to pass the prescribed checks the modulator must be replaced DIAPHRAGM 7C 42 Figure 7C 2 Vacuum Modulator Assembly 1 Bellows Comparison Check To check bellows load proceed as follows a Insert one end of the comparison gage J 24466 into the suspected modulator sleeve Insert the opposite end of the gage into a known good modulator of the same part number as the suspected modulator This part number of the modulator assembly is located on the back side of the modulator b Holding the modulators in a horizontal position see Figure 7C 3 bring them slowly together under pressure The modulator bellows in question if bad will reach the center line of the comparison gage before the know
57. ring gear to output shaft and output ring gear to output shaft snap ring See Figure 7C 140 DO NOT OVER STRESS SNAP RING ON ASSEM BLY ALWAYS USE NEW RING ON REASSEMBLY 2 Install reaction carrier to output ring gear needle thrust bearing with lip side face up See Figure 7C 141 1975 BUICK SERVICE MANUAV eambBuick com Figure 7C 139 OUTPUT RING coat LE NEEDLE THRUST BEARING 5B7C123 Figure 7C 141 3 Install output ring gear to case u Ick CO350 3758 TRANSMISSION See Figure 7 142 Lip on inner race of bearing MUST point toward rear of transmission Figure 7C 142 4 Install reaction carrier assembly into output ring gear and shaft assembly See Figure 7C 143 REACTION CARRIER X i daf OUTPUT RING GEAR AND OUTPUT SHAFT 7C 209 Figure 7C 143 5 Install output shaft and reaction carrier assembly into case Installing Low and Reverse Clutch Plates NOTE Refer to specifications in rear of this section to determine the required amount of lined and steel clutch plates to use with specific transmission model and engine combination When replacing piston assembly specific part number must be used 7C 47 1 Oil and install low reverse clutch steel separator plates and faced plates starting with a steel plate and alternating with faced plates See Figure 7C 144 LOW AND REVERSE CLUTCH PACK Figure 7C 144 2 Install low and
58. roughly with clean compressed air 4 Remove filter assembly and gasket 5 Install new oil filter to valve body gasket on filter Install new filter assembly 6 Install new gasket on oil pan and install pan Tighten attaching bolts to 13 Ib ft 7 Lower car and add 3 pints of transmission fluid through filler tube 8 With manual control lever in Park position start en gine DO NOT RACE ENGINE Move manual control lever through each range 9 Immediately check fluid level with selector lever in Park engine running and vehicle on LEVEL surface 10 Add additional fluid to bring level to 1 4 below the ADD mark on the dipstick Do not overfill Turbo Hydra Matic 350 375B Towing Instructions If a Buick equipped with Turbo Hydra Matic 350 375B transmission must be towed the following precautions must be observed The car may be towed safely on its rear wheels with the shift lever in neutral position at speeds of 35 miles per hour or less under most conditions However the drive shaft must exa en B u Ick CQ380 375B TRANSMISSION towed on its front wheels if tow speeds in excess of 35 mph are necessary Car must be towed for extended distances over 50 miles or Transmission is not operating properly If car is towed on its front wheels the steering wheel should be secured to keep the front wheels in a straight ahead position Rocking Car If it becomes necessary to rock the car to free it from
59. s section to determine the required amount of lined and steel clutch plates to use with specific transmission model and engine combination When replacing piston assembly specific part number must be used Disassembly of Direct Clutch 1 Remove intermediate overrun clutch front retainer ring and retainer See Figure 7C 96 O VERRUN CLUTCH RETAINING RING DIRECT CLUTCH ASSEMBLY ee Figure 7C 96 2 Remove intermediate clutch overrun outer race See Figure 7C 97 ww eambBuick CoOts8o 3758 TRANSMISSION 7 35 INTERMEDIATE OVERRUN ROLLER OUTER RACE 7C 162 Figure 7C 97 3 Remove intermediate overrun roller clutch assembly See Figure 7C 98 INTERMEDIATE OVERRUN ROLLER CLUTCH ASSEMBLY DIRECT CLUTCH DRUM 7C 163 Figure 7C 98 4 Remove direct clutch drum to forward clutch housing needle roller bearing See Figure 7C 99 5 Remove direct clutch pressure plate to clutch drum retaining ring and pressure plate See Figure 7C 100 6 Remove lined and steel plates from direct clutch hous ing See Figure 7C 101 7 Inspect condition of lined and steel plates Do not diagnose a lined drive plate by color Dry lined plates with compressed air and inspect the lined surfaces for 7 36 1975 BUICK SERVICE maw I eamBuick com pL ao S c ndi DIRECT CLUTCH DRUM TO FORWARD CLUTCH HOUSING NEEDLE ROLLER BEARING LINED PLATES Figure 7C 101 J 2590 3 J 2590 5 DIRECT CLUTCH
60. sand mud or snow move the selector lever from D to R in a repeat pattern while simultaneously applying moder ate pressure to the accelerator Do not race engine Avoid spinning wheels when trying to free the car REMOVAL OF OIL PAN OIL FILTER AND VALVE BODY WITH TRANSMISSION REMOVED Removal of Oil Pan 1 Remove 13 oil pan attaching screw and washer assem blies oil pan and gasket See Figure 7C 23 Figure 7C 23 Removal of Oil Filter 1 Remove two 2 filter assembly to valve body attaching screws See Figure 7C 24 Figure 7C 24 2 Remove filter assembly and gasket from valve body See Figure 7 25 Removal of Vaive Body 1 Remove detent roller and spring assembly from valve 2 Remove valve body from case while carefully guiding 7 19 Figure 7C 25 body Remove valve body to case attaching bolts See Figure 7C 26 Figure 7C 26 manual valve link from range selector inner lever Remove detent control valve link from detent actuating lever 3 Remove valve body to spacer plate gasket See Figure 7C 27 4 Remove spacer support plate bolts Remove spacer sup port plate See Figure 7C 28 5 Remove valve body spacer plate and valve body spacer plate to case gasket See Figure 7C 29 Be sure to note position of the four 4 plastic check balls so they are assembled correctly MAJOR REPAIR TRANSMISSION ASSEMBLY REMOVAL AND INSTALLATION Removal 1 Place transmission in neutral
61. spring spring seat and spring retainer Install detent valve stop and detent valve actuating bracket Torque bolt to 52 Ib in Assemble detent actuating lever with retaining pin 4 Install the pressure regulator valve spring reverse and modulator boost valve intermediate boost valve boost valve sleeve and retaining pin 5 In the next bore up install 2 3 shift valve shift valve spring 2 3 shift control valve shift control valve spring shift control valve sleeve and retaining pin 6 In the next bore up install the 1 2 shift valve 1 2 shift control valve control valve spring control valve sleeve and retaining pin 7 In the next bore up install the manual low control valve spring plug and retaining pin 8 In the top right hand bore install the detent regulator valve spring seat spring and retaining pin 3 gt TRANSMISSION 7 45 ASSEMBLY OF TRANSMISSION FROM MAJOR PARTS AND UNITS General Instructions 1 Before starting to assemble the transmission make cer tain that all parts are abso utely clean Keep hands and tools clean to avoid getting dirt into assembly If work is stopped before assembly is completed cover all openings with clean cloths 2 When reassembling it is important that all thrust washer surfaces be given an initial lubrication Bushings should be lubricated with transmission fluid Thrust wash ers should be lubricated on both surfaces with petroleum jelly
62. ter Drive Gear and Propeller Shaft Yoke Seal 1 Place speedometer drive gear retaining clip into hole in output shaft See Figure 7C 163 d SPEEDOMETER DRIVE GEAR J 23103 PROPELLER SHAFT YOKE SEAL OUTPUT i SHAFT F Figure 7C 164 Figure 7C 162 k SPEEDOMETER OUTPUT re SHAFT EXTENSION HOUSING TO CASE OIL SEAL 7 83 Figure 7C 163 Figure 7C 165 7C 52 1975 BUICK SERVICE MANU e arm Histic Kenaa driven gear retainer and bolt 2 Align slot in speedometer drive gear with retaining clip and install See Figure 7C 163 3 Install propeller shaft yoke seal 375B only using Tool J 23103 See Figure 7C 164 Installing Extension Housing 1 Install extension housing to case square cut O ring seal See Figure 7C 165 2 Attach extension housing to case using attaching bolts Torque to 35 Ib ft See Figure 7C 166 NOTE Extension has studs for the catalytic converter support on the right side A amp B Series N DUNS READ eo rts k Gp ds EXTENSION HOUSING 70 82 Figure 7C 166 Figure 7C 167 Torque bolt to 12 Ib ft Installing Parking Pawl and Actuating Rod 1 Install parking pawl tooth toward the inside of case See Figure 7C 167 2 Install parking pawl shaft into case through disengaging spring Install disengaging spring on parking pawl and slide shaft through parking pawl See Figure 7C 168 DISENGAGI
63. ter hub lip seal if neces sary and discard See Figure 7C 87 10 Place pump on wood blocks so surface finish is not damaged and install pump to converter hub lip seal using Seal Driver J 21359 See Figure 7C 88 Make certain lip seal is not turn or nicked 11 Check oil pump bushing for nicks severe scoring or wear If bushing replacement is necessary remove as fol lows support pump on wood blocks Use Tool J 21465 17 and Drive Handle J 8092 press bushing out of pump body www 1 0 75 TRANSMISSION PUMP TO CONVERTER HUB LIP SEAL PUMP BODY WOOD BLOCK 7 150 Figure 7 87 J 21359 PUMP TO CONVERTER HUB LIP SEAL PUMP BODY WOOD BLOCKS 7C 151 Figure 7C 88 To install new oil pump bushing use Tool J 21465 17 and Drive Handle J 8092 and press bushing into pump body from gear pocket face until it is flush to 010 below opposite face Front Pump Seal Side See Figure 7C 89 12 Check front stator shaft bushing for nicks severe scor ing or wear If bushing replacement is necessary remove as follows Assemble bushing remover J 21465 15 to adapter J 2619 4 Assemble this assembly to Slide Ham mer J 2619 Clamp Slide Hammer into vise Grasp stator shaft and remove bushing See Figure 7C 90 13 Install front stator shaft bushing as follows Support pump assembly on J 21424 7 before installing bushing Install bushing into the front end of stator shaft Using Installer
64. tes at engine speed The converter pump is an integral part of the converter housing therefore the pump blades rotating at engine speed set the oil within the converter into motion and direct it to the turbine causing the turbine to rotate As the oil passes throughout the turbine it is traveling in such a direction that if it were not redirected by the stator it would hit the rear of the converter pump blades and impede its pumping action So at low turbine speeds oil is redirected by the stator to the converter pump in such a manner that it actually assists the converter pump to deliver power or multiply engine torque As turbine speed increases the direction of oil leaving the turbine changes and flows against the rear side of the stator vanes in a clockwise direction Since the stator is now impeding the smooth flow of oil its roller clutch releases and it revolves freely on its shaft Once the stator becomes inactive there is no further multiplication of engine torque within the converter At this point the converter is merely acting as a fluid coupling as both the converter pump and turbine are being driven at approxi mately the same speed A hydraulic system pressurized by a gear type pump pro vides the working pressure required to operate the friction elements and automatic controls CONVERTER ASSEMBLY CONVERTER PUMP TURBINE FILTER STATOR INPUT SHAFT OIL PUMP COVER OIL PUMP BODY
65. ure plate should be used to have a clearance between 011 and 082 If the clear ance checks out to be between 011 and 082 no change of pressure plate is necessary DISASSEMBLY AND REASSEMBLY OF SUN GEAR TO DRIVE SHELL Disassembly of Sun Gear to Drive Shell 1 Remove sun gear to sun gear drive shell rear retaining ring See Figure 7C 124 SUN GEAR RETAINING SUN GEAR DRIVE SHELL Figure 7C 124 SUN GEAR DRIVE SHELL FLAT THRUST WASHER Figure 7C 125 See Figure 7C 125 J Remove front retaining ring from sun gear See Figure 7C 126 EN SUN GEAR ASSEMBLY i SUN GEAR eee DRIVE SHELL 7C 194 7 Figure 7C 126 If sun gear bushings replacement are necessary remove with a cape chisel See Figure 7C 127 PLASTIC MALLET CAPE CHISEL SUN GEAR BUSHING SUN GEAR DRIVE SHELL 7C 195 Figure 7C 127 Install sun gear bushings using Tool J 23062 3 J 8092 and install flush to 010 below counterbores See Figure 7C 128 Reassembly of Sun Gear to Drive Shell 1 Install sun gear to drive shell front retaining ring and install into drive shell See Figure 7C 126 Use a new ring and do not overstress when installing SUN GEAR DRIVE SHELL J 8092 J 23062 3 SUN GEAR ASSEMBLY 70 196 Figure 7C 128 Bushing Installation 2 Install sun gear to drive shell flat thrust washer See Figure 7C 125 3 Install sun gear to sun gear drive shell rear retaining ring See
66. vent damage to converter See Figure 7C 83 2 Install cooler by pass spring check ball and seat Using Tool J 23112 press seat into bore until top of seat is flush with face of pump body See Figure 7C 94 3 Assemble pump cover to pump body See Figure 7C 82 4 Install intermediate clutch piston inner seal and outer seal See Figure 7C 81 5 Install intermediate clutch piston assembly into pump cover with the aid of a piece of 020 music wire crimped into copper tubing J 21465 ADAPTER J 23062 PUMP COVER AND STATOR SHAFT ASSEMBLY 5B7C156 Figure 7C 93 PUMP BODY J 23112 7C 158 Figure 7C 94 6 Install spring retainer and install five 5 attaching bolts finger tight See Figures 7C 80 and 7C 79 7 Place pump aligning strap J 21368 over pump body and cover and tighten 8 Tighten attaching bolts Torque to 18 Ib ft 9 Install pump outside diameter to case square cut O ring seal See Figure 7C 86 Use new square cut O ring seal 10 Install three 3 direct clutch to pump hub hook type oil seal rings Inspect two 2 forward clutch to pump hub teflon oil seal rings for service if rings require replacement use hook type cast iron rings See Figure 7C 80 11 Check three 3 pump cover hub lube holes Make certain they are not restricted See Figure 7C 95 2 Figure 7C 95 DISASSEMBLY AND REASSEMBLY OF DIRECT CLUTCH NOTE Refer to specifications in rear of thi
67. wn or to rear of transmission ROLLER LOW AND REVERSE CLUTCH CLUTCH SUPPORT ASSEMBLY 7C 204 Figure 7C 131 7 44 1975 BUICK SERVICE E A T BAG Mave assembly with cored face up HA STS 3 Install low and reverse clutch to cam retaining ring See Figure 7C 132 4 Install low and reverse clutch to sun gear drive shell thrust washer See Figure 7C 129 VALVE BODY DISASSEMBLY INSPECTION AND REASSEMBLY Disassembly of Valve Body Refer to Figure 7C 133 Transmission need not be removed from car to perform the following operations LOW amp REVERSE ROLLER CLUTCH RETAINING RING Figure 7C 132 2 Remove manual valve from lower left hand bore J 3 From lower right hand bore A remove the pressure regulator valve train retaining pin boost valve sleeve in termediate boost valve reverse and modulator boost valve pressure regulator valve spring and the pressure regulator valve 4 From the next bore B remove the 2 3 shift valve train retaining pin sleeve control valve spring 2 3 shift control valve shift valve spring and the 2 3 shift valve 5 From the next bore C remove the 1 2 shift valve train retaining pin sleeve shift control valve spring 1 2 shift control valve and the 1 2 shift valve 6 From the next bore E remove retaining pin plug manual low control valve spring and the manual low control valve 7 From the next bore F
68. www eamBuiCk COMgso 3758 TRANSMISSION 7 1 TURBO HYDRA MATIC 350 375B AUTOMATIC TRANSMISSION CONTENTS DESCRIPTION AND OPERATION Description of Turbo Hydra Matic 350 375B Automatic Transmission 7C 1 DIAGNOSIS Sequence for Turbo Hydra Matic 350 375B Transmission Diagnosis 7C 3 Turbo Hydra Matic 350 375B Transmission Oil Checking Procedures 7C 3 External Qil Leaks sehe taii tete ee estet re ED ee danas 7C 3 Vacuum Modulator Diagnosis Procedure seen 7C 4 Turbo Hydra Matic 350 375B Trouble Diagnosis Chart 7 5 Hydraulic Pressure CheckS 2 saa ua ua akaqa aa aaa aT pass 7C 12 MAINTENANCE AND ADJUSTMENTS Detent Cable Adjustment 5 eret a re e DR LE EAR 7C 16 Removal of Propeller Shaft Yoke Seal Speedometer Drive Gear and Governor 7C 17 Fluid Recommendations Refer to O Section Maintenance Removal of Oil Pan Oil Filter and Valve Body sess 7C 19 MAJOR REPAIR Transmission Assembly Removal and Installation sees 7C 19 Preliminary Instructions RED altel dea Corne celta C 7C 20 Removal of Converter Holding Tool Converter and Vacuum Modulator 7C 21 Removal of Extension Housing Lip Seal and Bushing sse 7C 22 Installing Extensi
69. y compressing with a ram press See Figure 7C 115 FORWARD CLUTCH DRUM 7C 184 Figure 7C 117 5 Inspect the return springs Evidence of extreme heat or burning in the area of the clutch may have caused the springs to take a heat set and would justify replacement of the springs 6 Remove forward clutch piston assembly See Figure 7C 117 7 Remove forward clutch piston inner and outer seals See Figure 7C 118 FORWARD CLUTCH PISTON INNER SEAL 7C 185 Figure 7C 118 8 Make certain forward clutch ball check exhaust is free of dirt etc See Figure 7C 120 9 If the input shaft is scored it may be replaced using the following procedure www TRANSMISSION 7C 41 FORWARD CLUTCH BALL CHECK EXHAUST FORWARD CLUTCH DRUM 7C 186 Figure 7C 120 a Using wood blocks for support press input shaft out of forward clutch housing b Taking care support forward clutch housing on rear thrust washer surface and press input shaft into housing until it is properly seated c Runout at rear thrust washer surface should be no more than 005 NOTE The input shaft and forward clutch housing are serviced separately Reassembly of Forward Clutch Assembly 1 Install the forward clutch inner piston seal and outer piston seal See Figure 7C 118 2 Install the forward clutch piston assembly with aid of a piece of 020 music wire crimped into copper tubing See Figure 7C 12

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