A-Type Overdrive service instruction manual
Contents
1. Theoperating valve plug is placed at the top right hand side of the overdrive casing If the previous checks have all been satis factory this plug should now be removed BEFORE REMOVING THE PLUG IT IS VERY IMPORTANT TO RELEASE ALL OIL PRESSURE FROM THE SYSTEM BY OPERATING THE VALVE SETTING LEVER BY HAND ABOUT TEN TIMES After removing the plug spring and plunger the steel ball will be seen in the bottom of the valve chamber a small magnet will be found use ful for removing the ball from the chamber To remove the valve a short length of wire approximately 2 3812 mm diameter It is sealed with a screwed plug A and contains a spring THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT should be inserted into the drilling in the centre of the valve which can then be lifted out Clean and examine the valve seats If necessary the ball seat G on the operating valve can be re finished by gently grinding a spare 7 937 mm diameter steel ball using a fine grade grind ing paste Do NOT use the actual ball from the unit for grinding in and be sure to wash the valve seat clean before refitting it If necessary the ball should be reseated in the valve chamber by tapping it gently on to the seat F using a soft copper drift 4 OVERDRIVE DOES NOT RELEASE Important es If this happens do not try to move the car because a transmission lock would occur in reverse and damage may result i2. diameter bolts the head of the bolts are painted RED REMOVE THE NUTS FROM THE STUDS BEFORE TOUCHING THE BOLTS The two bolts should now be slackened off together releas ing the compression on the accumula tor spring which abuts the solenoid bracket g The pump valve plug F can now be unscrewed with a box spanner and the spring D plunger C and ball B removed Fig 6 THE LAYCOCK DE NORMANYVILLE OVERDRIVE UNIT After re assembling it will be necessary to reset the solenoid lever as described on page 8 2 OVERDRIVE ON ALL GEARS i Electrical Control Gear 7 9 zi Fig 6 The Oil Pump h Clean the valve seat A and reseat the ball if necessary by gently tapping it on to its seat with a copper drift Re assembly is the reverse of the above operations but ensure that the valve plug 1s well tightened on to the soft copper washer E Fig 6 which should be replaced by a new one if damaged in any way Do not forget to replace the accumulator spring tube when re assembling failure to do so will result in the piston housing becoming displaced as soon as the unit is driven Also ensure that the end of the accumulator spring engages on the short dowel at the rear of the solenoid bracket a A dangerous condition can arise if that part of the circuit between W2 Fig 5 onthe relay to the non earthed side of the isolator switch becomes accidentally earthed Any earthing wou
3. to pass over its roller on the pump plunger The operating cam should be assembled on the gearbox mainshaft s splines so that the eccentric is offset from the ball race this is obviously necessary to allow the cam to align with the pump roller The driving plunger on the overdrive unit should be slowly revolved by hand as the splines on the gearbox mainshaft approach those in the overdrive unit The forward ends of the six thrust springs having been located on their respective spigots a nut and washer is fitted on the end of each of the long studs and the nuts tightened down evenly and progressively so as to pull the two units together When the two faces are within 1 of each other the pump plunger should be depressed with one screwdriver whilst the cam is pushed along its splines with a second screwdriver into alignment with the roller on the plunger and both screwdrivers can then be with drawn Continue tightening the gearbox down on the overdrive unit until it is possible to engage nuts on the threaded portion of the remaining studs Fit nuts and washers and tighten all nuts home together progressively CAUTION Do not use undue force in tightening the nuts on the long studs There are two sets of splines in the overdrive unit and unless these are in line it is impossible to tighten the overdrive unit home on to the adapter plate face The overdrive valve setting should now be checked FITTING THE SO
4. top gear on TR2 and the ignition switched on If C2 remains dead connect W2 to earth If C2 becomes alive then either the operating switch or the isolator switch is faulty If lt C2 remains dead then the relay is faulty and should be replaced Re move the test wire from W2 to earth c If the switches are suspected remove from the terminal of the isolator switch situated on the O S of the _ gearbox except TR2 the wire which is NOT earthed and connect it directly to earth If C2 becomes alive then the operating switch is satisfactory and the isolator switch is faulty and should be replaced If C2 remains dead then the operating switch is faulty and should be replaced d If when 2 is alive the solenoid 1s too weak to move the lever its full travel see valve adjustment or sets up a continuous buzzing noise or fails to operate at all then it should be re placed by a new solenoid which has been weather proofed or fitted with the latest type of rubber shroud No Oil Pressure If the unit still fails to operate and the operating valve is seating and lifting cor rectly check that the oil pump is working Jack up the rear wheels of the car remove the operating valve plug and start the engine Before removing the plug it is very important to release all oil pres sure from the system by operating the valve setting lever
5. Blocked Restrictor Jet in the Operating Valve A symptom of this is failure to get back into normal or a slow return to normal drive as the oil slowly leaks out through the blocked jet The cure is to remove the operating valve as already described and clear the Jet ii Electric Control not operating cor rectly If the unit remains in overdrive after the ignition has been switched off then the electrical circuit is not at fault If however the unit cuts in and out with the ignition switch a short circuit in the wiring or a faulty relay must be looked for See 2 G iii Solenoid Lever not set correctly or Solenoid Plunger sticking It is very unlikely that any maladjustment of the lever will develop to prevent over drive from releasing Make sure that there is 1 6 35 mm clearance between the solenoid adjusting screw E Fig 8 and the head of the solenoid bolt when the plunger is lifted The setting and working of the valve setting lever should be checked as already described and corrected if necessary iv Sticking Cone Clutch This fault has been known to occur as a result of heating up after a long run on a new unit before the linings are fully bedded in The clutch invariably releases itself when it has cooled down a little or it can be released by giving the casing a sharp blow with a hide hammer over the brake ring between the body of the overdrive and the rear cover s
6. CLUTCH SLIP IN OVERDRIVE i Insufficient oil in Gearbox The correct oil level must be maintained ii Solenoid Lever not set correctly Check the setting as already described iii Insufficient Hydraulic Pressure Probably due to foreign matter on the ball seat of the pump valve or on the ball seat ing on the operating valve Check the pressure with the adapter and gauge as already described and clean and reseat valve if required iv Worn or burned Cone Clutch Outer Lining This is not experienced even after very large mileages unless the car has been driven for a long time in overdrive with the clutch slipping due to causes i 11 or ii given above Removal of the unit and re placement of cone clutch member would be necessary in this case 6 CLUTCH SLIP IN REVERSE OR FREE WHEEL CONDITION ON OVER DRIVE Blocked Restrictor Jet in Operating Valve causing sluggish return move ment of the Cone Clutch Clean the restrictor jet as already described STRIPPING AND REBUILDING THE OVERDRIVE The overdrive can only be removed from the geargox by splitting at the adapter plate leaving the plate attached to the gearbox The nuts should be removed from the four short studs before touching those on the two long studs Then these should be unscrewed simul taneously a few turns at a time to release the compression on the clutch return springs Operations 1 and 2 can be carried out without completely strippin
7. by hand about ten times Engage top gear with the engine the TR2 ticking over slowly and watch for oil being pumped into the valve chamber If none appears then the pump is not working probably due to foreign matter on the seat of the non return valve A flow of oil into the operating valve chamber does not prove that the oil pressure is correct a pressure of 470 510 lbs per sq in 32 9 35 7 kgs per sq cm is required on the Vanguard and Renown and 420 445 lbs per sq in 29 4 31 1 kgs per sq cm is required on An adapter is available and should be used to replace the operating valve plug in conjunction with an oil pres sure gauge reading up to 800 lbs per sq in 56 24 kgs per sq cm and suitable for screwing into the 4 B S P thread in the mouth of the adapter Low pressure in dicates leakage To remedy this fault proceed as follows a Remove the drain plug G and drain off oil Fig 6 b In the case of the TR2 remove the cover from solenoid bracket c Remove solenoid On the Vanguard and Renown remove solenoid from its mounting bracket and on no account attempt to unscrew the two RED painted bolts holding the bracket at this stage d Slacken off clamping bolt in solenoid lever and remove lever with the sole noid plunger attached e Remove the distance collar f The solenoid bracket is secured by two 5 7 937 mm diameter studs and two 5 7 937 mm
8. circlip previously used a new one will be required when re assembling When a new 2nd or 3rd mainshaft gear is to be fitted ensure that 004 006 end float of the gears is permitted by the length of their bushes when in their fitted position Having ensured that the synchro units are perfectly free on their splines check the overall float of the constant mesh assemblies by removing the 2nd and 3rd speed constant gears but leaving their respective bushes in position with the hardened steel washer and the half circlip Checking overall float of mainshaft bushes with feeler guage k D Fig 33 THE LAYCOCK DE The end float can then be checked with a set of feeler gauges as shown in Fig 32 The correct float should be between 007 and 012 Remove the mainshaft details remain ing on the shaft and begin the final assembly Fit the triangular shaped washer ball race distance washer and circlip Feed the shaft into the casing and assemble the Ist gear synchro unit the hardened steel thrust washer which must be located on the splines the 2nd constant gear with its bush the 3rd constant gear with bush the front hardened steel thrust washer and finally fit the main locating circlip with a special sleeved tool Withdraw the gearbox mainshaft with the gears so far assembled sufficiently towards the rear to enable the assembly to be tipped upwards thus permitting the 3rd and top
9. cone clutch contacts the an nulus to prevent free wheeling When the throttle is closed the cone clutch is released from contact with the brake ring and takes up the drive smoothly against the annulus THE ELECTRICAL CONTROL GEAR Fig s Wiring Diagram The operating valve lever is lifted auto matically by the plunger of an electric solenoid The solenoid has two separate coil windings with an internal switch which is closed when the solenoid is not energised The closing coil gives a powerful initial lift to open the valve after which the internal switch opens leaving the holding coil to continue holding the valve open The current to operate the solenoid is taken from TO STARTER SOL SWITCH WHITE FEED SIDE body is a press fit into the overdrive front casing and is fed with oil from the sump of the casing through a fine mesh strainer The oil is delivered through a non return ball valve to the accumulator cylinder in which a piston moves back against a powerful compression spring until the required pressure of 470 510 lbs per sq 32 9 35 7 kgs per sq cm the case of the Vanguard and Renown and 420 445 Ibs per sq in 29 4 31 1 kgs per sq cm in the case of the TR2 is reached when relief holes are uncovered From the relief holes the oil is led through drilled passages in the overdrive body to an annular groove between the two steady bushes for the gearbox shaft extension
10. plate Where it has been found necessary to drill the oil transfer hole the adapter plate and paper packing should now be removed and the casing and joint faces carefully cleaned Having first fitted the reverse pinion and ensured the condition of the countershaft gears drop this latter assembly into the casing with a needle roller retainer tube inside it to position the needle rollers with the front and rear thrust washers located by the tip of the countershaft and in grease respectively The countershaft gears should have an end float of 006 010 in their fitted position If there is insufficient float the distance collar should be reduced Where the end float is excessive a new distance washer and or thrust washer should be fitted 18 10 11 12 13 14 15 16 17 Fig 34 identified by colouring the outer ones Having ensured the correct float in the countershaft gears the countershaft should be driven out towards the front of the unit by the retainer tube sufficiently to allow the countershaft gear assembly to fall to the bottom of the casing whilst permitting the tip of the shaft to support the front thrust washer The smaller rear washer remains located in grease The retainer tube should be tapped a sufficient distance into the countershaft gear to locate the 24 needle rollers at each end whilst permitting the assembly to drop to the bottom of the casing Remove the mainsha
11. punch marks are radially outward as shown in Fig 22 The sun wheel Fig 24 Inserting the Dummy Mainshaft The next thing is to select a suitable adjustment washer to allow the correct amount of end float to the sun wheel The steel thrust washer B Fig 25 which is fitted between the bronze thrust washer C Fig 25 and the central bush 4 Fig 4 in the main casing serves also to make this ad justment and is supplied in various thicknesses to suit the assembly Gauging the end float of the sun wheel Fig 22 Positioning the Marked Teeth on the Planet can be done easily with ordinary feeler Wheels gauges as follows Fig 23 Dummy Mainshaft Churchill Tool No L 185 should now be inserted into the planet carrier and with the punch marks still outward the planet carrier should be placed into the annulus The dummy shaft Fig 23 should now be inserted and left in place until rebuilding is Fig 25 Selecting a suitable Adjustment Washer to completed Fig 24 give the Sun Wheel End Float 16 Fig 26 THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT Place the bronze washer C Fig 25 and the steel washer B Fig 25 in position at the front of the sun wheel The cone clutch A Fig 25 should be left out while the thrust washer is being selected Place the extra steel adjustment washer D of known thick ness on top of the steel washer B and offer up the main casing assembly to the tail c
12. springs are correctly located as shown in Fig 34 that is the long springs on the outside and the short springs nearer the centre The dummy shaft should now be withdrawn and the unit is ready for fixing to the gearbox If not required for immediate fixing to the gearbox the adapter plate or wooden cover should be fitted before putting the unit into store TO EFIT OVERDRIVE TO VANGUARD MODEL Remove the gearbox leaving the engine in position With Series II models there is a detachable portion at the rear of the normal detachable floor pressing the removal of which in addition to that of the main pressing enables the gearbox to be removed and replaced without disturbing the clutch The removal of the gearbox with earlier models necessitates the withdrawal of the clutch before the gearbox can be lifted upwards and over the floor of the car The gearbox should now be dismantled and the various gears and ball races examined 17 for possible damage Any parts which are damaged or suspect in any way should be replaced Where the vehicle which is being converted to incorporate overdrive has covered a mileage in excess of 10 000 miles serious consideration should be given to the fitting of a reconditioned gearbox Remove the mainshaft ball race if this has not already been done during normal dis mantling work The mainshaft originally fitted will be replaced by the special one supplied THE LAYCOCK DE NORMANVILLE OVERDR
13. IVE UNIT Fit the baulk pin plate and ball race on the new mainshaft Gripping the mainshaft in the suitably protected jaws of a vice assemble the gears on this shaft up to the main locating circlip ensuring that the recess for this is free for its eventual entry by checking with half the circlip previously used a new one will be required when When a new first or second mainshaft gear is to be fitted ensure that 004 006 end float of the gears is permitted by the length of their bushes when in their fitted positions Having ensured that the synchro unit is perfectly free on the splines check the overall float of the constant mesh assemblies remove the second and first constant gears but leaving their respective bushes in position with the hardened steel washer and half circlip The end float can then be checked with a set of feeler gauges as shown in Fig 32 The correct float should lie between 007 and 012 On the assumption that the oil transfer hole from the gearbox casing to the overdrive unit has yet to be drilled fit the gearbox rear end packing and assemble adapter plate supplied in the conversion pack on to the gearbox casing securing the plate temporarily with the bolts provided Drill diameter oil transfer hole in dicated in Fig 33 it will already be drilled during normal manufacture with the later Series II models concentrically through the hole in the adapter
14. LENOID AND BRACKET 1 Remove the collar on the valve operating shaft by withdrawing the cotter pin which is located on the N S of the overdrive unit Remove the side cover plate by FIRST REMOVING THE TWO NUTS and then the two gt diameter bolts the heads of which are painted RED The two bolts should be slackened off together releasing the pressure on the accumulator spring After fitting the rubber grommet to the actuating bolt screw this bolt into the solenoid plunger until the cotter pin hole is in mid position in one of the slots of the plunger Do not fit a cotter pin at this stage Fit the pressure plate over the grommet and with two diameter screws position on the solenoid bracket Fig 27 EID SOLENOID LEVER SOLENOID BRACKET COLLAR OIL SEAL RUBBER GROMMET SOLENOID PLUNGER SOLENOID Z a og 2 2 DIA SCREWS L SRN PRESSURE PLATE Fig 27 Exploded view of Solenoid operating details 5 Fit a paper joint treated with jointing com pound and thesolenoid over the plunger and over the two diameter screws protruding through the solenoid bracket Fit suitable nuts spring washers and tighten up Fit the solenoid lever to the actuating bolt as shown in Fig 28 Fig 28 Solenoid Operating Details in assembled form 10 11 THE LAYCOCK DE After making sure that the paper Joint is correctly placed and in good condition locate the s
15. OVERDRIVE ii Solenoid Lever not set correctly Fig 7 The solenoid lever once set should not normally require any further adjustment Checking the setting of the lever takes only a few seconds and should be carried out at this point in case any initial bedding down has caused maladjustment On the opposite side of the overdrive to the solenoid will be seen a valve setting lever C mounted on the end of the valve operating shaft D In the outer end of the lever is a S T aaa Ht Setting the Operating Valve 4 7625 mm diameter hole A which must line up with a similar hole B in the overdrive casing when the lever is in the correct overdrive position To check this setting switch on the ignition with the gear lever in the neutral position Switch overdrive switch to the on position top gear on TR2 this will then operate the solenoid and move the valve operating shaft to the overdrive position The hole in the setting lever should now be in line with the hole in the overdrive casing and it should be 7 possible to insert a 4 7625 mm dia meter pin or drill shank into the two holes If the holes do not line up the solenoid lever must be reset Proceed as follows a Remove the cover plate from the solenoid bracket in the case of the TR2 There is no cover plate on the Van guard or Renown b Slacken off the c
16. Radial holes in the shaft collect the oil and deliver it along an axial drilling to other radial holes in the shaft providing positive pressure fed lubrication to the sun wheel thrust washers planet carriers and planet bearings From the ISOLATOR SWITCH OPERATING SWITCH I SYR we 9 6 RELAY CONTACTS O C2 TO AMMETER IF FITTED BROWN WIRE BATTERY SIDE CLOSING COIL WHERE NO AMMETER 1S a INTERNAL FITTED RUN TO BROWN SWITCH BLUE ON HEAD LAMP SWITCH Fig 5 the starter solenoid switch and the operating switch in the case of the Vanguard and Triumph Renown is situated on the steering column but on the TR2 this switch is placed on the instru ment panel Incorporated in the circuit is an isolator switch which limits the use of overdrive to top and second on the Vanguard and Renown and to top gear only on the TR2 THE HYDRAULIC SYSTEM The hydraulic system is supplied with oil by a plunger type pump operated by a cam on the gearbox mainshaft extension The pump 4 HOLDING COIL Wiring diagram accumulator cylinder oil under pressure is sup plied to the operating valve chamber by way of a drilled passage in the unit casing When the operating valve is lifted the oil flows under pressure via another drilled passage to the two operating pistons which work in cylinders formed in the unit casing When the operating valve is closed the oil in the operating cylin
17. SERVICE INSTRUCTION MANUAL for the LAYCOCK DE NORMANVILLE OVERDRIVE UNIT WITH ELECTRICAL CONTROL 7 DARD THE STANDARD MOTOR COMPANY LIMITED COVENTRY ENGLAND THE STANDARD MOTOR CO LTD Registered Office BANNER LANE COVENTRY WARWICKSHIRE ENGLAND Telegrams STACK COVENTRY Telephone TILE HILL 66611 Car Division CANLEY COVENTRY Telegrams FLYWHEEL COVENTRY Telephone COVENTRY 3181 Spares Division FLETCHAMSTEAD COVENTRY Telegrams FLYWHEEL COVENTRY Telephone COVENTRY 62471 Coventry Service Depot ALLESLEY COVENTRY Telegrams STANSER COVENTRY Telephone COVENTRY 2115 London Service Depot STANDARD ROAD CHASE ESTATE PARK ROYAL N W 10 Telegrams STANTRI NORPHONE LONDON Telephone ELGar 6511 London Sales 15 17 BERKELEY SQUARE LONDON W 1 Telegrams FLYWHEEL WESDO LONDON INDEX Page Description 2 2 eae s 1 4 The Principle TT aa 1 Operation 22 ee a Construction Be Ege Se eG mn a 2 The Electrical Control Gear ee ees 4 The Hydraulic lata ae 4 Care and Lubrication ee ae we Diagnosis and Rectification of Faults ig E 1 Overdrive does not engage a aga Steen C 3 2 Overdrive on all gears a me 3 Overdrive does not remain engaged nd 4 Overdrive does not release ws a 10 5 C
18. UN TO BROWN SWITCH BLUE ON HEAD LAMP SWITCH Fig 41 the gearbox lid A second feed wire is connected from the negative side of the ammeter to Cl on the relay To complete the wiring a wire is connected from C2 on the relay through a snap connecter to the solenoid Built into the solenoid are two coils a closing coil and a holding coil These two coils are connected in parallel with an internal switch connected in series with the closing coil When the solenoid is energised both coils are in circuit until the plunger reaches a pin which operates the internal switch This 26 HOLDING cow Overdrive Control Circuit _ switch switches out the closing coil and allows the holding coil to remain in circuit The closing current of 15 amperes is of a very short duration The holding current should be less than one ampere Fig 41 shows the theoretical wiring diagram GENERAL With a four speed gearbox no useful purpose can be gained by over driving any gear other than top since the differential ratio of 2nd to 3rd and 3rd to top is almost the same as that of the over drive No provision is made for over driving any gear other than top gear nor is it recommended NORMANVILLE OVERDRIVE UNIT THE LAYCOCK DE w T K 5 1 Ise I 4 s 9 9 09 92 esas Se Fig 42 The Overdrive in exploded form Inset shows Accumulator Piston Spring and S
19. as detailed on in structions enclosed with each conversion kit IMPORTANT Under no circumstances must an attempt be made to incorporate overdrive in second without fitting the Baby Accumulator This is equally important when using a manually operated system I 2 THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT TO FIT OVERDRIVE UNIT TO TRIUMPH TR2 DISMANTLING Remove the detachable floor pressing from around the gearbox Remove the four bolts connecting the propeller shaft to the gear box flange drive from the gearbox Remove the bottom nuts of rear mounting and jack up engine sufficiently to allow removal of rear mounting Remove the starter motor Remove the clevis pin from the lever on the clutch withdrawal shaft Remove the bolts from around the bell housing and detach the gearbox from the engine The gearbox should now be dismantled and the various gears and ball races examined for possible damage Any parts which are damaged or suspect in any way should be replaced Remove the mainshaft ball race if this has not already been done during normal dis mantling work The mainshaft originally fitted will be replaced by the special one supplied ASSEMBLY OF GEARBOX Proceed to re assemble in the following sequence a Fit Ist and reverse idler pinion and shaft with the smaller gear pointing forward and the hole in the shaft in line with the securing bolt b Fit the reverse selector f
20. asing assembly It will not go right down because of the extra washer and the gap left between the two casings should be measured with feeler gauges Fig 26 Gauging the Sun Wheel End Float The width of the gap will be equal to the thickness of the extra washer less the amount of the sun wheel end float for example if the extra washer used 15 078 1 981 mm thick and the meas ured gap between the casings is 062 1 575 mm then the end float of sun wheel with the particular thrust washer used will be 078 minus 062 equals 016 1 981 mm minus 1 575 mm equals 406 mm The end float of the sun wheel must be between 014 and 020 355 mm and 508 mm It is advisable when re assembling a unit to first of all try the original thrust washer taken from the unit If the end float is found to be too much too little a suitable washer can readily be selected by calculation These are supplied in various thick nesses As soon as the end float of the sun wheel is correct re assembly can quickly be completed Separate the two casings remove the extra thrust washer fit the cone clutch assembly A Fig 25 in place offer up the main casing to the tail casing fit the nuts and spring washers on to the studs and tighten up evenly The bridge pieces for the operating pistons should now be fixed in place and the clutch thrust springs placed in position on the pegs Ensure that the eight
21. ders is returned to the sump THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT CARE AND LUBRICATION The oil in the overdrive is common with that in the gearbox The oil to use 15 is ordinary mineral oil in the following grades Normal summer climates Normal winter climates 30 S A E 20 Under no circumstances should extreme pressure gear oils be used because the cent rifugal effect of the planets m y separate some of the additives from the oil and cause sludging The oil capacity of the gearbox and overdrive unit is as follows Standard Vanguard and u Triumph Renown 34 pints 2 litres Triumph TR2 31 pints 2 litres The correct level must be carefully main tained It will be necessary to remove the drain plugs from both gearbox and overdrive unit to drain them but refilling is done through the gearbox only Refill the gearbox with oil after draining and then drive the car a short distance after which top up with oil because some of the oil will have been taken into the hydraulic system Do not run the car with no oil in the unit because air may enter the hydraulic system Cleanliness is the keynote to satisfactory performance of any hydraulic system The smallest amount of dirt or fluff from a wiping cloth which finds its way into a valve will cause a great deal of unnecessary difficulty Pay particular attention to the clean condition of the oil used for filling and care
22. drive unit mesh with those of the mainshaft The eight springs are now located on their spigots and a nut and washer fitted to each long stud These two nuts are now evenly tighten ed until the pump roller is nearing the pump driving cam The driving cam should have been assembled on the gearbox mainshaft splines so that the least amount of eccentricity is nearest to the pump roller It is necessary to depress the pump plunger with a screwdriver to allow the pump roller to pass over the cam The nuts are now finally tightened CAUTION Do not use undue force in tightening the nuts on the long studs There are two sets of splines in the overdrive unit and unless these are in line it is impossible to tighten the overdrive unit home on to the adapter plate face The overdrive valve setting should now be checked VALVE CHECKING On the O S of the overdrive unit and pinned to the valve operating shaft is a valve setting lever with a diameter hole In the casting adjacent to this lever is another gt diameter hole Actuate the solenoid with a 12 volt battery and while the plunger is drawn into the solenoid and if the valve adjustment is correct it should be possible to insert diameter pin through the valve setting lever and into the casting see 36 If this is not possible then the valve must be _re adjusted in the following manner VALVE ADJUSTMENT Remove the cover plate b
23. e driving shaft In overdrive the outer member of the roller clutch over runs the inner member Engine braking is again provided by the cone clutch which holds the sun wheel from rotating CONSTRUCTION Fig 4 The mainshaft of the gearbox is extended to form the input shaft 1 of the overdrive unit This shaft carries first of all a cam 3 operating a plunger type hydraulic pump 39 The pump delivers oil through a non return valve 36 to the accumulator cylinder 35 in which a piston 34 moves back against a compression spring 33 until the required pressure is reached when relief holes are uncovered Further back on the shaft there is a freely rotatable sun wheel 17 in one piece with an externally splined sleeve Immediately behind the sun wheel and splined to the shaft is the planet carrier 15 in which are mounted the three planet wheels 16 At the rear of the input shaft and also splined to it is the inner member 20 of the roller clutch The outer member 18 of the roller clutch is carried in the annulus 32 which is in one piece with the output shaft 23 Mounted on the splined sleeve of the sun wheel is a double cone clutch member 11 The cone clutch member can slide upon the splined sleeve of the sun wheel so that the inner lining 14 can make contact with a cor responding cone on the annulus alternatively the outer lining 12 can make contact with a cast iron brake ring 13 which forms part of th
24. e unit housing To the hub of the cone clutch member is secured a ball bearing 9 housed in a flanged thrust ring 10 This ring carries on its forward face eight pegs 7 acting as guides to eight com pression springs 8 by which the cone clutch member is held against the annulus The thrust ring also has attached to it four pins 5 which carry two bridge pieces 6 bearing against the pistons 2 operating in cylinders formed in the unit casing The pistons can push in the op posite direction to the thrust of the springs and are connected through a valve to the pressure accumulator In direct gear the drive from the input shaft is through the rollers 19 of the roller THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT A 12 13 gere ASANA ALAD ho _ gt 5 SQ lt x SS 7 i dru us 35 clutch which rise up the inclined faces of the inner member and become wedged between the inner and outer member of the clutch The inner lining of the cone clutch is held locked by spring pressure against the annulus so that the entire gear train rotates as a solid unit to prevent a free wheel condition and to handle reverse torque The change into overdrive is effected by operating a switch which in turn actuates the solenoid Whilst the plunger is drawn into a solenoid this rotates the operating shaft 28 so that the cam lever 37 li
25. ear of the unit It is possible to guide it past the guide peg by means of a screwdriver in serted through the side of the casing Removing and Refitting the Operating Piston and its Housing Remove the solenoid bracket as previously described and lift out the accumulator spring and spring tube The accumulator piston housing B is a push fit into the unit casing and the oil tightness of the housing is ensured by the two rubber Fig 13 Piston Housing and Extractor Churchill Tool No L 182 Fig I4 THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT The housing can be extracted easily to gether with the piston by the use of the special tool E which fits into the bore of the housing and has a rubber O ring D which can be expanded by turning the tommy bar F To use the extractor first remove the operating valve plug A Fig 9 to admit air to the rear of the housing insert the nose of the extractor as far as it will go into the bore of the housing tighten the tommy bar and pull Fig 14 Extracting the Piston Housing Examine the bore of the housing for signs of wear such as a ridge or scoring This examination should be carried out without removing the piston from the housing The accumulator piston is fitted into the housing at the works with a special venturi tube which ensures that the piston rings do not scrape the surface as they enter the aluminium housing Replacement pist
26. eater switch when fitted oe R H Drive Cars Two holes are pierced in the facia panel on the R H side of the speedometer and covered with fabric The fabric should be pierced through the ex treme R H hole and the operating switch fitted see Fig 39 The remaining hole is used for a heater switch when fitted The Relay Reference to Fig 40 shows the fitted position of the relay Wiring The feed wire to the terminal marked W1 on the relay is taken from 25 Fig 39 Showing the position of the Overdrive Control the live side of the starter switch on the facia panel see Fig 41 NOTE The terminal the starter switch is live only when the ignition is switched ON o A wire is connected from W2 on the relay to a terminal of the operating switch on the facia panel The remaining terminal Fig 40 Instructions for fitting the Relay Switch fe of the operating switch is connected through a snap connecter to a terminal on the isolating switch situated on the gearbox lid The remaining terminal of the isolating switch is earthed to one of the bolts securing THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT TO STARTER SOL SWITCH WHITE FEED SIDE OPERATING SWITCH ISOLATOR SWITCH e a RELAY CONTACTS e Ci c2 TO AMMETER IF FITTED BROWN WIRE BATTERY SIDE CLOSING S CoOL lt WHERE NO AMMETER 15 INTERNAL FITTED R
27. el splined extension E Fig 2 and it is pushed by springs to engage with the corresponding cone of the annulus F This therefore locks the sun wheel to the annulus Between the annulus and the sun wheel are the planet wheels which are carried by the planet carrier G which is mounted on the driving shaft B The planet wheels are therefore also locked and resistance to over run is provided by the engine through the gearbox and main drive shaft to the planet wheels HYDRAULIC PRESSURE Fig 3 When overdrive is engaged Fig 3 a valve in the unit is opened applying hydraulic pres sure from the pressure accumulator to two pistons which work in cylinders formed in the unit housing These pistons exert pressure against the cone clutch member overcoming the spring pressure and pushing the cone clutch D away from the annulus until the outer lining B presses against a conical brake ring A built into the main casing The sun wheel which carries on its splined extension the cone clutch is free to rotate on the driving shaft therefore when the cone clutch comes into contact with the brake ring both cone clutch and sun wheel are brought to rest and held stationary in either direction Overdrive in operation The planet carrier C which is splined to the driving shaft is driven round the stationary sun wheel so that the planets rotate and over drive the annulus at a higher speed than th
28. ft details remaining on the shaft with the exception of the ball race and baulk pin plate and fit into the gearbox casing Assemble mainshaft constant mesh gears on the shaft and install main locating circlip with the special sleeved tool Withdraw the gearbox mainshaft with the gears so far assembled sufficiently towards the rear to enable the assembly to be tipped upwards thus permitting second and top synchro unit to be fitted Tap mainshaft assembly into position and fit constant pinion Raise countershaft gear assembly and fit countershaft and complete re assembly of the unit Fit adapter plate and locate packing on the gearbox casing with grease Wire the heads of the six securing bolts as shown in Fig 33 The correct positioning of the wiring is important to ensure proper working clear ance of the assembled overdrive unit Ensure that the eight springs in the over drive unit are correctly located as shown in Previously these springs were being painted red and the inner or shorter ones blue This method of identification is no longer necessary as the middle springs are appreciably shorter than those fitted at the top and bottom of the casing Fit the gearbox assembly to the overdrive unit holding the latter in a vice as shown in Fig 35 It is necessary to depress the pump plunger with a screwdriver whilst carrying THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT out this operation in order to allow the cam
29. fts the operating valve spindle 38 admitting oil from the pressure accumulator cylinder into the two cylinders in the unit casing pushing the operating pistons 2 against the bridge piece 6 The cone clutch member now overcomes the eight clutch springs and slides forward along the splines of the sun _ 15 26 v 2829 30 Fig 4 Sectional View of the Overdrive Unit 33 3l wheel extension until the outer lining 12 con tacts the stationary brake ring 13 The oil immersed cone clutch comes smoothly to rest together with the sun wheel resulting in a perfectly smooth change into over drive During the brief period of time when the change into overdrive is taking place the power continues to be transferred through the rcller clutch until overdriving actually com mences so that the drive is without interruption and the change instantaneous When changing from overdrive to direct drive the throttle may be kept open The release of oil pressure from the operating cylinders is deliberately restricted so that the cone clutch takes about half a second to move over to the direct drive position As soon as contact between the cone clutch and the brake ring is broken the load on the engine is released allowing the engine to speed up until THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT the roller clutch ceases to be over run and takes up the drive again The change into normal is completed as the
30. fully clean all around the filler plug each time before removing it Regular attention to these small details will be rewarded by long and trouble free service DIAGNOSIS AND RECTIFICATION OF FAULTS Any faults in the overdrive or its control gear will become manifest in one or other of six symptoms These six symptoms are given below and each one is covered by a procedure for finding and rectifying the fault in the quickest possible time The tests given are arranged in such an order as to avoid any unnecessary dismantling or removal of parts As familiarity with the overdrive increases al most any fault can be isolated and rectified within a short time Each of the tests given is based on the assumption thai the previous tests have been satisfactorily carried out and that the unit has been working normally prior to the fault developing When 3 unit has been removed from the gearbox and replaced other faults can occur due to wrong assembly but these faults are given separately in the sections dealing with fitting stripping and rebuilding of the overdrive OVERDRIVE DOES NOT ENGAGE Insufficient oil in the unit The gearbox must be filled to the level of the filler plug Be sure to clean carefully around filler hole before removing plug ii Solenoid Lever not set correctly See page 8 iii Electrical Control Gear When the electrical components are func tioning correctly the solenoid can be heard
31. g the unit they have been included in this section for convenience THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT Fig 10 Inserting the Oil Pump Extractor Churchill I Tool No L 183 Removing and Refitting the Oil Pump Fig 10 Remove the solenoid bracket as previously described and lift out the accumulator spring and tube to give access to the oil pump non return valve Remove oil pump non return valve plug spring plunger and ball F Remove oil drain plug D and the oil strainer B which is held in place with the long bolt C Now take out the special screwed plug E and the two oil pump body screws G Screw the short threaded end of the extractor bolt into the oil pump body in place of the special screwed plug Turn the wing nut on the long screwed end of the extractor bolt A drawing out the pump body Fig 11 Fig 11 Extracting the Oil Pump 1 Fig 12 Inserting the Oil Pump using Churchill 2 Tool No L 184 To replace the oil pump body which is an interference fit in the casing use two number 10 U N F studs about 3 7 5 cm long A as guides and drive the pump body B home with a suitable brass drift or use the special tool which incorporates the two guides Fig 12 The pump plunger is prevented from rota tion when in position by a guide peg carried in the front casing When assembling the pump the plunger should be inserted with the flat on its head facing the r
32. he operating pistons and rings are not damaged The Gear Train Inspect the teeth of the gear train for damage Examine the bronze bush in the sun wheel which should be a close running fit on the mainshaft and examine the planet wheels which should be a close running fit on the planet pinions If the sun wheel or planet bushes are worn they cannot be replaced in service because they have to be bored true to the pitch line of the gear teeth The gear train comprising sun wheel planet carrier with planets and annulus is only supplied for service as a matched assembly to ensure quiet running and care should be taken when dismantling units to keep gear trains in sets b The Mainshaft Inspect splines for wear or burrs examine for signs of wear where the shaft runs in the bushes and sun wheel See also that the oil holes are open and clean Cone Clutch Sliding Member As sembly Examine the clutch linings for burning wear or embedded foreign matter The linings cannot be replaced in service because they have to be c d 13 S ground accurately after riveting to the cone clutch member which must be replaced if necessary See also that the cone clutch slides freely on the splines of the sun wheel extension Make sure that the pins for the clutch springs and bridge pieces are riveted tightly into the clutch thrust ring and that the thrust ring ball bearing is in good condition e Clutch Springs Examine fo
33. he switch should NOT be moved and that the change should be from overdrive second to overdrive top and then the switch can be moved to normal top if desired In changing down 21 OVERDRIVE UNIT Showing the assembled position of Control Switch Fig 31 from overdrive second to normal second the road speed MUST NOT exceed 40 m p h NOTE When fitting an overdtive t to early Vanguard and Triumph cars it is necessary to carry out slight alterations to the floor toe board and in some cases the chassis cross member Details of these alterations are outlined in Overdrive Fitting Instructions Part No 500955 which may be obtained from our Spares Department The necessary parts to enable Electrical Con trolled Overdrive to be fitted are supplied in packs for the convenience of Agents Two different packs are supplied The first under Part No 501877 is to enable a car not previously fitted with Overdrive to be equipped with an electrically controlled unit and the second Part No 501878 to convert a car already fitted with a manually controlled Laycock De Normanville Unit In the case of a conversion it is merely necessary to fit the Baby Accumulator and to discard the existing operating cable and con trol details on the overdrive unit itself see The Standard Motor Co s Publication Part No 501927 The existing normal gear changing mechanism will be retained as it is fitted apart from slight modifications
34. il this free travel is reduced to NOTE The correct operation of this isolator switch locknut It is important that there should is most important as operation in reverse will be lost movement at this point seriously damage the unit 20 THE LAYCOCK DE NORMANVILLE FITTING THE RELAY 1 Fit the relay to the relay bracket using two self tapping screws The bonnet hinges are secured to the body by three bolts to each hinge The bottom bolt of the hinge nearest to the steering column is used to hold the relay and bracket inside the car Fig 30 Fig 30 Showing the por Moning and wiring for the Relay 2 From the hinge bolt remove the nut fit the relay and bracket with the three connections uppermost Refit the nut and tighten in this position 3 The circuit shown in Figs 5 and 41 shows the connections to be made to the relay FITTING THE OPERATION SWITCH The operating switch is fitted between the gear change top clamp bracket and the under side of the steering wheel with the lever pointing in the opposite direction to the gear shift see Fig 31 It may be necessary to move the gear change mechanism lower down the steering column to accommodate the switch One wire is fed through a snap connecter to the isolator switch and the remaining wire should be con nected to W2 on the relay CAUTION It is of the utmost importance that when changing from high speeds in overdrive second t
35. ing into the tail casing put the distance washer 24 Fig 4 on to the annulus shaft and press home the rear bearing 25 Fig 4 These dis tance washers are supplied in various thicknesses to suit the assembly First of all try the same distance washers which were taken off when dismantling even if a new annulus has been fitted the original distance washer will prob ably be suitable Drive on the coupling flange and tighten the slotted nut The end float of the annulus must now be measured using either a dial indicator or by inserting feeler gauges between the annulus and a straight edge placed across the front face of the tail casing The end float must be 005 to 010 It is very im portant that no preload should develop on the annulus bearings when the unit warms up in use If the end float falls outside these limits the nut and flange must be removed the annulus driven out and a different spacing washer selected When the end float is correct remove the nut and flange and press home the oil seal 26 Fig 4 which 15 006 26 mm interference fit The lip of the oil seal should face inwards Next prepare the main casing assembly In the following order Assemble the oil pump with valve etc the ac cumulator housing with piston ac cumulator spring tube and solenoid bracket as already described Next fit the two operating pistons using a small piston ring clasp to assist assem bly or Churchill T
36. l A planet wheels B a planet wheel carrier D and an outer ring the annulus Fig I Principle of an Epicyclic Gear If the planet carrier is rotated while the sun wheel is locked to the annulus the whole gear train will rotate as a solid unit giving a direct through drive If on the other hand the sun wheel is locked to the casing preventing it from rotating and the planet carrier is rotated the annulus will be overdriven at a higher speed than the planet carrier OPERATION In addition to an epicyclic gear train similar to the one depicted in Fig 1 there is also a hydraulic pump a hydraulic accumulator or pressure storage chamber a roller clutch and a sliding cone clutch When in direct top gear see Fig 2t the overdrive Is inoperative The Fig 2 Operation in Direct Drive THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT drive from the gearbox to the propeller shaft is taken through the rollers A from the gearbox main driving shaft B to the outer member of the uni directional clutch C and so direct drive is transmitted The roller clutch drives in one direction only and therefore if the car were to over run the engine the rollers would be pushed down the inclined surfaces away from the annulus or output member and the drive broken leaving the car without engine resistance to assist braking This problem is overcome by means of a cone clutch D This clutch slides on the sun whe
37. lamping bolt A in the solenoid lever c d e f UNIT Energise the solenoid as already de scribed and put a 7 4 7625 mm diameter pin through the hole in the valve setting lever into the hole in the casing Hold the solenoid lever C downwards so that it bears lightly against the head of the plunger bolt D and tighten the clamping bolt A Adjusting the Solenoid Lever Make sure that there is no end float in the valve operating shaft by pressing the valve setting lever and the solenoid lever inwards simultaneously when tightening the solenoid lever bolt This expands the oil seals and prevents oil leakage Remove the pin from the setting lever and operate the solenoid several times by use of the switch Check that the hole in the valve setting lever corresponds with the hole in the casing by inserting the pin again If the two holes do not quite line up a g O Fig 9 THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT fine adjustment can be made by screw ing the solenoid plunger bolt D further in or out of the plunger To adjust this bolt it will be necessary to remove and replace the split pin which secures the two parts After ensuring that the setting is cor rect replace the cover to the solenoid bracket The adjusting screw E is to prevent the plunger bolt from falling too low when the solenoid is not energised The screw should be set to give 1 6 35
38. ld bring in the overdrive on al gears including reverse Any attempt at reversing the car in overdrive would destroy the roller clutch built into the unit If such a situation should occur remove the wire from W2 until the fault has been located and rectified b Built into the relay are switch contacts which switch the heavy current to the solenoid when the solenoid coil 1s energised Should these contacts stick IN then the overdrive would be operative on all gears including re verse To check this remove the wire from W2 and check C2 If C2 is alive then the contacts are sticking in Replace the relay If the solenoid plunger has corroded due to the entry of water into the solenoid the plunger could stick IN causing overdrive on all gears To check this remove the wire from C2 and by working the solenoid lever on the side of the gearbox ensure that the plunger is working freely in and out of the solenoid Should tlx e be any tightness ensure that the lever is not putting any side load on the actuating bolt thereby jamming the plunger in the bore of the solenoid Should any tightness remain remove the solenoid from the bracket and check the plunger for corrosion Should any corrosion be apparent replace the solenoid with one which has been weather proofed or fitted with the latest type of rubber shroud Fig 7 THE LAYCOCK DE NORMANVILLE
39. lutch slip in overdrive ee ee 6 Clutch slip in reverse and free wheel condition on overdrive onp np 0 Stripping and Re building the tate Be 10 17 Removing and Refitting Oil Pump 10 11 Removing and Refitting Operating Piston and Housing 11 12 Dismantling the Body and Gears _ ae 12 13 INSpeCHUOn sss dia T 13 Re assembling Unit 13 17 To fit Overdrive Unit to Gearbox of Vanguard 17 To fit Overdrive Unit to Gearbox of Triumph TR2 22 FOREWORD This Manual has been compiled with a view to familiarising our Agents and other Repairers throughout the World with the operation and repair of the Laycock de Normanville Overdrive Unit Whilst there have been few major changes in the Overdrive Unit itself since it was first fitted to our vehicles there have been alterations in the control mechanism This Manual deals with the Electrical Control mechanism currently fitted to the Standard Vanguard Triumph Renown and Triumph TR2 Details of earlier control mechanisms are included in two previous publications entitled Instructions for Fitting Laycock de Normanville Overdrive Unit and supplied under Part Numbers 500955 and 501545 respectively obtainable from our Spares Department x Detailed overhaul instructions are given in this Manual mainly for the benefit of our Overseas Dealers who are unable to
40. mm clearance between the head of the plunger bolt and the end of the _ screw when the plunger is lifted Oo nm VGA WW gt The Operating Valve 3 OVERDRIVE DOES NOT REMAIN G ENGAGED Operating Valve leaking due to foreign matter on the Valve Seat The operating valve chamber Fig 9 is an enlargement at the top of a vertical hole in the overdrive casing and plunger C which hold a steel ball D downwards against a seating F to prevent oil from circulating to the operating cyl inders The valve J is a hollow spindle sliding in the hole with a conical seating G for the steel ball in the top end When the valve is lifted by the cam lever K it seats against the ball which is then lifted ad mitting oil from the pressure accumulator via the drilled passage E to the passage L and into the operating cylinders moving the pistons forward to engage the cone clutch When the valve is lowered the ball is allowed to come on to its seating in the casing cutting off the supply of oil from the accumulator Further lowering of the valve brings it out of contact with the steel ball allowing the oil from the operating cylinders to return along passage L and down inside of the valve to discharge through the small re strictor Jet H into the sump of the over drive body The jet is of such a size that the cone clutch takes about half a second to move back under the influence of the clutch springs
41. n Piston Ring Accumulator Piston Accumulator Spring Large Accumulator Spring Small Solenoid Bracket and Side Cover Assembly Operating Solenoid Solenoid Lever Plunger Screw Cover Plate SPECIALISED TOOLS The following tools are recommended for the dismantling and assembly of the Laycock de Normanville Overdrive Unit They are manufactured by Messrs V L Churchill Ltd 27 34 Walnut Tree Walk London S E 11 to whom all enquiries should be addressed L 176 Drive Shaft Oil Seal Remover L 177 Drive Shaft Oil Seal Replacer L 181 L 182 L 183 L 184 L 185 L 186 L 188 L 189 L 178 Accumulator O Ring Fitting Tool Accumulator Piston Housing Remover Pump Barrel Remover Pump Barrel Replacer Dummy Drive Shaft Mainshaft Bearing Replacer Hydraulic Pressure Gauge Freewheel Assembly Ring Freewheel Transfer Ring
42. nd Renown range but on top gear only on the Triumph TR2 which has a four speed gearbox The electrically operated overdrive on the two upper gear ratios with the Three Speed Unit offers a number of improvements an instantaneous gear change at the touch of the operating switch a five speed gearbox namely first second overdrive second top and over drive top a speed range in second gear of five to forty five miles per hour and a cruising ratio overdrive top giving approximately 30 m p E at 50 m p h In the case of the TR2 which has a four speed gearbox no useful purpose can be gained by overdriving any gear other than top since the differential ratio of second to third and third to top is almost the same as that of the overdrive No provision is made for over driving any gear other than top gear nor is it recommended overdrive unit itselfi IS fitted t to the rear of the normal gearbox and takes the place of the normal rear extension on all models RATIOS 208 20ST Models 00x 16 tyres f 2nd Ist Rev Ratios 1 00 1 67 3 54 411 Overall BS Ratios 4 625 771 16 35 18 99 When in O Drive 36 600 TR2 5 75 16 tyres Top 3rd 2nd lst Rev Ratios 1 00 1 325 2 00 3 38 4 28 _ Overali Ratios 3 7 49 74 125 15 8 When in O Drive 3 03 THE PRINCIPLE Fig 1 An epicyclic gear train is arranged to con sist of a sun whee
43. olenoid arrangement 21 for the Triumph TR2 NOTATION EOR EIG 42 Description Mainshaft Adapter Plate Paper Joint Bolt Drain Plug Fibre Washer Bolt for Filter Filter Plug for Pump Body Oil Pump Body Pump Spring Oil Pump Plunger Assembly Bridge Piece Oil Pump Operating Cam Stud Operating Piston Main Casting Stud Stud Welch Washer Valve Spring Copper Washer Valve Plug Stud Accumulator Piston Housing Accumulator Spring Tube Accumulator Spring Joint Washer Side Cover Collar for Shaft Clutch Springs Long Clutch Springs Short Spacing Washer Brake Ring Clutch Thrust Ring Assembly Clutch Sliding Member O Qn IS OONA Q to Zy s e O Py Ref No 37 Description Planet Carrier complete with Planet Wheels Bearing Shafts etc Thrust Washers Pin Uni directional Clutch to Cage Inner Member Uni directional Clutch Cage for Uni directional Clutch Spring for Uni directional Glutch Cage Thrust Washer Annulus Sub assembly Ball Bearing Spacing Washer Ball Bearing Oil Seal Rear Casing Sub assembly Operating Valve Plunger for Ball Stud Thrust Washer Spacing Washer Steel Roller Stud Setscrew Rubber O Ring Oil Seal Seeger Circlip Seeger Circlip Ball Bearing Accumulator Pisto
44. olenoid bracket assembly on the side plate by using the two red painted bolts fit to the casting and at the same time feed the oil seal collar and solenoid lever on to the valve operating shaft Tighten the and fit a cotter pin to the collar diameter holes coincide and then a gt inserted through the lever into the casting thus locking the shaft Fig 36 Actuate the solenoid with a 12 volt battery and while the plunger is drawn into the solenoid fit the clamping bolt and secure the lever to the operating shaft Remove the pin from the valve setting lever and disconnect the battery Re connect the battery and check the position of the valve setting lever again which should permit the re entry of the pin through the lever into the casting If the holes do not coincide note which way the lever should moved and then remove the solenoid the plunger and screw the actuating _ bolt whichever way is necessary Re 12 _ assemble and repeat the check satisfied that the holes exactly correspond When with the solenoid energised remove the when not in overdrive and then tighten the NORMANVILLE OVERDRIVE UNIT FITTING THE ISOLATOR SWITCH Fig 29 1 Disconnect the first and reverse cross shaft from the gearbox flange Unscrew the tapered locking bolt and remove the flange from the gearbox Remove two x 3 A C bolts 2 Fit the isolator switch to
45. ons are supplied already assembled in the housing The piston should not be taken from the housing but should this happen inadvertently do not put the piston back by pushing it into the rear end of the housing which has a conical recess C Fig 13 as this may result the piston rings scraping the aluminium as they enter the housing Instead put the piston back from the front end of the housing using a small piston ring clamp to compress the rings as the piston enters A special venturi tube is now supplied by V L Churchill under Tool No L 179 12 Push the new piston and housing together into the casing by hand using the ac cumulator spring tube 26 Fig 42 to push witb This will ensure that the piston does not blow out backwards as the housing goes in In the case of the TR2 where there is overdrive for top gear only remove the solenoid bracket as previously described Draw out the two accumulator springs 66 and 67 Fig 42 The piston has diameter N F 2 tapped hole in its underside A long bolt or length of screwed rod should be screwed into the piston in order to with draw it Assembly is the reverse procedure and it is important to appreciate that correct fitting of the piston rings is of vital im portance to the efficient working of the unit Check that the rings are not gummed up due to use of an unsuitable lubricant or have excessive clearance in the grooves Dismantling the Body and Gear
46. ool No L 179 The operating valve ball plunger spring and plug should now be fitted Finally drive home the cast iron brake ring using a hide hammer Fig 16 The brake ring is spigoted to the main casing and is a light interference fit jointing composition should not be used Assemble the sliding clutch member Press the ball bearing B into the housing in the thrust ring A and secure with the external circlip D The thrust ring and bearing is then 14 TNS Driving home the Brake Ring pressed on to the cone clutch member C and secured with the internal circlip E using suitable circlip pliers Fig 17 Fig 17 Assembling the Sliding Member d Assemble the roller clutch This is quite easily done with the special assembly ring Fig 18 The roller clutch inner member A cage B and spring are put together making sure that the spring is in the right way sO as to cause the cage to urge the rollers up the inclined faces of the inner member See note on page 15 The inner member with cage and spring is then placed into the assembly ring and the rollers C are pushed in through the slot in the rim of the ring Fig 19 The roller clutch can then be THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT transferred direct from the assembly ring to the annulus remembering to put the bronze thrust washer A Fig 20 into position first Figs 20 and 21 Fig 18 Freewheel As
47. ork and shaft with the tapered hole forward Secure in position by fitting the tapered bolt and locknut c With heavy grease assemble the needle rollers into the Ist countershaft gear 24 each end and slide in a needle retaining tube to retain the rollers during assembly d With heavy grease position the front thrust washer with the lip of the washer engaged with a recess in the gear case e Slide the small or 2nd speed gear on to the Ist countershaft gear following this by the 3rd speed gear with the boss pointing forward Next slide on Disconnect the speedometer f g h Fig 32 the distance piece and finally the con stant speed gear with the boss towards the distance piece Position the completed layshaft gear assembly in the bottom of the gear case and slide into position the rear thrust washer For checking purposes the layshaft should now be fitted The counter shaft gears should have an end float of 006 010 in their fitted position After checking the layshaft should be removed by pushing the needle re taining tube into the countershaft gears and forcing the layshaft out after which the gears should drop to the bottom of the gear casing Gripping the new mainshaft in the suitably protected jaws of vice assemble the gears on this shaft up to the main locating circlip ensuring that the recess for this is free for its eventual entry by checking with half the
48. r dis tortion or collapse Free length should be 43 11 5 cm outer springs 41 10 8 cm inner springs Replacement springs are supplied only in sets f Roller Clutch See that the rollers are not chipped or damaged and that the inner and outer members of the roller clutch are not damaged The outer member of the roller clutch can not be replaced in service because it has to be ground concentrical to the an nulus after being fitted See that the spring is not distorted or broken Replacement rollers are supplied only in sets g Ball Bearings See that the ball bearings for the annulus are in good condition and free from roughness when rotated slowly h Thrust Washers Inspect for scoring of the steel or bronze i Oil Pump Examine the pump for signs of wear The pump plunger should be a close sliding hydraulic fit in the pump body and the plunger roller should rotate freely on the roller pin with no slackness Examine that the pump valve seat and ball are free from nicks and scratches j Operating Valve See that the ball seating is free from nicks and scratches and the restrictor jet clear Make sure that the valve slides freely in its bore in the front casing Re assembling the Overdrive Unit a First build up the tail case assembly drive the front ball bearing on to the annulus and then press the annulus b 127 to 254 mm THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT and bear
49. s At this point the front cover plate should have already been removed Remove the clutch thrust springs and the two operating piston bridge pieces Next remove the nuts from the six studs which hold the rear casing to the main casing and the two casings can then be pulled apart Fig 15 Fig 15 Separating the Casing The sliding cone clutch sun wheel planet carrier and roller clutch can now be lifted out in that order To remove the annulus from the rear casing grip the coupling flange in a vice and remove the large slotted nut from the end also remove 4 THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT the speedometer pinion assembly The annulus which can now be drifted out easily from the rear will take the front ball bearing with it and leave the rear ball bearing in the casing Inspection After the unit is dismantled and cleaned each part should be thoroughly inspected to decide which parts should be replaced a Front Casing Examine for cracks or damage oil leaks from the plugged ends of the oil passages or from the welch plug beneath the accumulator bore Examine the bronze support bushes in the centre bore in which the mainshaft should be a close running fit These bushes cannot be replaced in service since they have to be bored concentrical to the casing after fitting See that the cylinders which are bored in the casing for the operating pistons are free from scratches or scoring and that t
50. sembly Ring Churchill Tool No L178 Fig 21 Tail Casing with Roller Clutch assembled IMPORTANT NOTE The assembly of the roller clutch as shown in this Manual covers all the Triumph Sports Prefix No 1275 and Vanguard Overdrive Units which have prefix No 1327 Earlier Vanguards which have prefix No 1287 on the plate of the overdrive are fitted with the Fig 19 Assembly of Roller Clutch narrow roller clutch Assemly of this unit differs slightly as the lip on the outer cage is towards the rear of the unit and a locating peg on the inner member locates in a corresponding hole in the planet carrier It will be seen therefore that after assembling the rollers as in Fig 19 it will be necessary to transfer the roller clutch into another ring Churchill Tool No L189 and then from this ring into the annulus This will then ensure that the lip on the outer cage is to the rear and the locating peg facing forward Fig 20 Transferring Roller Clutch to Annulus 15 THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT e Assembly of gear train Erect the tail case assembly by securely gripping the mounting flange in a vice Place the three thrust washers 38 2 off and 54 Fig 42 for the rear of the sun wheel into position inside the planet carrier with the steel thrust washer between the two bronze ones One tooth on each planet wheel is punch marked and the planet wheels must be turned in the carrier so that the
51. sitioning the Marked Teeth on the Planet Wheels Dummy Mainshaft Churchill Tool No L185 _ Inserting the Dummy Mainshaft Selecting a suitable Adjustment Washer to give the correct Sun Wheel End Float 0000 Gauging the Sun Wheel End Float Exploded view of Solenoid Operating Details Solenoid Operating Details in assembled form _ Isolator Switch fitted to prevent engagement of Over drive Control in First and Reverse Gear Showing the positioning and wiring for the Relay Showing the assembled position of Control Switch Checking overall float of Mainshaft Bushes with Feeler Gauge eta Showing the Oil Transfer Hole and method of wiring 0 22 ann anan san n Showing correct location of four Springs Fitting Gearbox to Overdrive Unit wn Method of setting Valve Operating Levers __ Setting Solenoid Lever l ee Showing position of the Isolator Switch on the Gear box Cover oo Showing the position of the Overdrive Control _ Instructions for fitting the Relay Switch _ Overdrive Control Circuit 9 2 0 The Overdrive in exploded form THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT AS FITTED TO PRESENT PRODUCTION OF 20S 20ST and TR2 MODELS DESCRIPTION The Laycock de Normanville Overdrive Unit fitted to the above models is electrically operated at the touch of an electric switch This unit operates on second and top gears on the Vanguard a
52. synchro unit to be fitted Tap the mainshaft assembly into position and fit the constant pinion assembly m Raise the countershaft gear assembly and fit layshaft and complete the assembly of the unit Showing the oil transfer hole and method of wiring bolts The Gearbox casing has to be drilled on early models whereas all present production are already drilled NORMANVILLE OVERDRIVE UNIT Fig 34 Showing correct location of four springs 3 FITTING THE OVERDRIVE UNIT a b c Locate the paper washer on the gearbox casing with grease fit the overdrive adapter plate and wire the six securing bolts as shown in Fig 33 The correct positioning of the wiring is important to ensure proper working clearance for the assembled overdrive unit Ensure that the oil transfer hole is free see Fig 33 Ensure that the eight springs in the overdrive unit are correctly located as shown in Fig 34 that is the long springs on the outside and the short springs nearer the centre After placing a paper joint on the adapter plate fit the gearbox assembly Fig 35 Fitting Gearbox to Overdrive Unit This operation is shown being carried out with a Vangaurd unit meter hole in the casting THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT to the overdrive unit holding the latter vertically in the vice as shown in Fig 35 After engaging top gear turn the constant pinion until the splines in the over
53. take advantage of our Replacement Unit Service To further assist Overseas Dealers who have to carry out their own repairs a fully comprehensive stock of parts for the Overdrive Unit and its control mechanism are obtainable from our Spares Department Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig Fig WNP ILLUSTRATIONS Principle of an Epicyclic Gear Operation in Direct Drive aes Overdrive in operation Sectional view of the Overdrive Unit Wiring Diagram tee The Oil Pump Setting the Operating Valve 2 000 Adjusting the Solenoid Lever The Operating Valve aaa tae Inserting the Oil Pump Extractor Churchill Tool No L183 1 1 2 Extracting the Oil Pump a Inserting the Oil Pump using Churchill Tool No 1184 Piston Housing and Extractor Churchill Tool No LI8 amp 2 l aaa s aaa Extracting the Piston Housing gw Separating the Casing 2 0 00 ee Driving home the Brake Ring was 2 Assembling the Sliding Member _ ns Freewheel Assembly Ring Churchill Tool No L178 Assembly of Roller Clutch 0 Transferring Roller Clutch to Annulus Tail Casing with Roller Clutch assembled __ Po
54. the bracket using Fit the stone guard to the two remaining two 1 bolts to replace those previously studs and tighten the nuts removed Replace flange and reconnect the o cross shaft ee on a TE ae shaft 2 3 Fit the isolator switch to the bracket and by valve setting lever with a 3 diameter hole using special packing washers adjust the In the casting adjacent to this lever is position of the switch until the plunger is another diameter hole The valve depressed 1 setting lever should be rotated until the two A wire should be run from one contact of the switch through a snap connector to the operating switch The remaining con tact should be earthed to the gearbox Fig 29 Isolator Switch fitted to prevent engagement of Overdrive Control in First and Reverse Gears solenoid fit the cotter pin to the actuating 5 With the change speed lever in neutral bolt and plunger and finally refit the position the isolator switch contacts are solenoid closed and remain closed in either top or E second gear position Fit the actuating bolt stop screw and lock When first or reverse gears are eee the nut Fig 28 By holding the operating isolator switch contacts are opened thus lever against the head of the actuating bolt making it impossible to overdrive either of and moving the lever a certain amount of these gears free travel should be felt Adjust the stop screw unt
55. to click in and out when the gear lever is in neutral the ignition switched on and the overdrive switch moved to the on and off positions Except TR2 See below When the gear lever is moved into first or reverse on all models except TR2 the circuit should become dead that 15 no clicking of the solenoid should be heard when the ignition is switched on and the operating switch moved to the on and off positions In the case of the TR2 the circuit becomes gear is engaged alive only when top The feed wires to W1 and C1 on the relay NOT connected through any fuse for the following reason Should the fuse blow when the engine is driven at peak revs in overdrive second gear the overdrive unit would immediately return to normal second gear The car run ning at high speed would then turn the engine at speeds for which it was not designed with consequent risk of damage to the connecting rods valve gear etc THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT iv Fault Locating See Fig 5 v a Check battery b Check the W1 terminal of the relay which should be alive when the ignition is switched on Check the Cl terminal on the relay which should always be alive Check the C2 terminal on the relay which should be alive only when the operating switch is in the overdrive position the gearbox in neutral
56. y U unscrewing three cheese headed bolts Slacken off the clamping bolt on the solenoid lever Rotate the valve setting lever until its 2 diameter hole coincides with the 33 dia in Insert a diameter pin through the hole in the Fig 37 VALVE CONTROL VER Fig 36 Method of setting Valve Operating Levers setting lever and into the casting thus locking the valve operating shaft Actuate the solenoid with a 12 volt battery and while the plunger is drawn into the solenoid tighten the clamping bolt on the solenoid lever and at the same time ensure that opposite end of the solenoid lever is against the head of the actuating bolt Repeat the first check and if satisfactory refit the cover plate see Fig 37 SOLENOID Setting Solenoid Lever THE LAYCOCK DE NORMANVILLE OVERDRIVE UNIT FITTING THE ISOLATOR SWITCH On the lid of the gearbox and situated near the dipstick is a plug with a 16 mm dia thread This plug should be removed and replaced by an isolator switch type SS10 1 which is supplied see Fig 38 Fig 38 Showing the position of the Isolator Switch on the Gearbox Cover 7 THE OPERATING SWITCH L H Drive Cars Two holes are pierced in the facia panel the L H side of the speedometer and covered with fabric The fabric should be pierced through the ex treme L H hole and the operating switch fitted The remaining hole is used for a h
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