Unit Overhaul

Transmission Disassemble

Tools Required
- J 8105 Gear Puller
- J 21427-01 Speedometer Gear Puller Adapter
- J 22912-01 Separator Plate
- J 23907 Slide Hammer and Adaptor
- J 36509 Detent Spring Plug Remover




1. Remove the two bolts which attach the idler shaft segment and the idler shaft support collar to the rear housing.




2. Remove the backup lamp switch from the rear housing.
3. Remove the bolt and the electronic speed sensor from the rear housing.
4. Remove the shift shaft block-out bushing pin from the front housing.




5. Use the J 36509 and the J 23907 in order to remove the following components from the front housing:
- The detent plug
- The spring
- The plunger
6. Slide the hammer with the 6 mm end into the hole in the front housing.




7. Remove the five bolts which secure the input shaft bearing retainer to the front housing.
8. Use the J 23907 to remove the input shaft bearing retainer from the front housing.
9. Remove the snap ring.




10. Remove the nine bolts which attach the front housing to the rear housing.
11. Angle the front housing up and press down on the rear housing in order to separate the front housing from the rear housing.
12. Remove the countershaft roller bearing from the countershaft or the bearing shell.




13. Remove the shift shaft lever roll pin from the shift shaft lever:
Rotate the shift shaft lever and the shift shaft bushing.

Important: Do not lose the shift shaft lever plunger or the spring when removing the shift shaft lever roll pin from the rear housing.

- Remove the shift shaft lever plunger and the spring.
- Support the shift shaft end while driving out the shift shaft lever roll pin.
- Allow the roll pin to clear the second gear during removal.

Notice: Do not use excessive force when removing the shift shaft. Excessive force will "peen" the shift shaft and damage the rear housing shift shaft bearing causing increased shift effort.

Important:
- Do not bend the shift rail when removing the roll pin.
- Use an air gun with a 5 mm (3/16 inch) drift punch in order to remove the roll pin.
- The roll pin will fall into the rear housing.

14. Remove the shift shaft socket roll pin from the bottom of the shift shaft socket.

Notice: Do not use excessive force when removing the shift shaft. Excessive force will "peen" the shift shaft and damage the rear housing shift shaft bearing causing increased shift effort.




15. Remove the following components:
- The shift shaft
- The shift shaft socket
- The lever
- The shift shaft block-out bushing
16. Rotate the third-fourth shift fork counterclockwise.
Remove the third-fourth shift fork.




17. Remove the five bolts which secure the output shaft bearing retainer to the center of the rear housing.
18. Remove the rear housing from the gear assemblies.
19. Remove the reverse idler gear assembly.
20. Remove the output shaft bearing retainer.
21. Remove the shift forks.
22. Remove the countershaft.
23. Remove the countershaft bearing snap ring.
24. Remove the countershaft bearing.
The countershaft bearing must be pressed OFF the counter shaft.
25. Remove the fifth counter gear from the counter shaft.




26. Use the J 21427-01 and the J 8105 to remove the speed sensor rotor from the output shaft.
27. Discard the speed sensor rotor.
28. Remove the snap ring from the output shaft.
29. Use the J 21427-01 and the J 8105 to remove the output shaft bearing from the output shaft.




30. Remove the fifth speed gear from the output shaft.
31. Remove the snap ring from the output shaft.
32. Remove the following components from the output shaft:
- The synchronizer blocking ring
- The synchronizer and the hub
- The synchronizer blocking ring The reverse speed gear assembly




33. Leave the synchronizer rings on the fifth-reverse synchronizer assembly in order to prevent the synchronizer detent balls from popping out.




34. Remove the input shaft and the pocket bearing from the output shaft.




35. Remove the snap ring.
36. Use a hydraulic press in order to remove the following components from the main shaft:
- The third-fourth synchronizer assembly
- The synchronizer blocking rings
- The third speed gear




37. Remove the following components from the main shaft:
- The retaining ring
- The pin
- The two thrust washer halves




38. Remove the second gear from the main shaft.
39. Remove the following components from the main shaft:
- The inner cone
- The middle cone
- The synchronizer ring




40. Remove the snap ring.

Important: Scribe the synchronizer hub to the output shaft prior to disassembly.

41. Use the J 22912-01 and a hydraulic press to remove the following components:
- The synchronizer
- The synchronizer ring
- The inner cone
- The middle cone The first gear




42. Leave the synchronizer rings on the first-second synchronizer assembly in order to prevent the synchronizer detent balls from popping out.




43. Remove the following components from the reverse idler shaft:
- The segment
- The gear
- The bearing assembly
- The collar
- The two O-rings from the shaft

Front Housing Disassemble

Tools Required
- J 23907 Side Hammer With Adapter
- J36511 Oil Plug Hex Bit (17mm)
- J 36800 Shift Shaft Bushing Remover

Notice: Do not remove the vent from the front housing. If the vent is damaged, the front housing must be replaced.

1. Remove the input shaft bearing from the front housing.




2. Use the J 23907 and the J 36800 in order to remove the shift rail front housing from the bushing.




3. Use the J 36511 to remove the oil fill plug.
4. Remove the gasket material from the housing.

Rear Housing Disassemble

Tools Required

- Hydraulic Press
- J 23907 Slide Hammer With Adapter
- J 26941 Output Shaft Oil Seal Remover
- J 36511 Oil Plug Hex Bit (17 mm)




1. Remove the snap ring.
2. Remove the shift shaft support.

Important: If the bearing lip breaks OFF, position the puller legs behind the inside (outer edge) of the bushing lip and repeat the procedure.




3. Use the J 23907 in order to remove the rear housing shift rail bushing from the rear housing.
1. Position the puller legs behind the bearing lip.
2. Tighten the puller legs.
3. Remove by pulling with the slide hammer.




4. Use the J 36511 in order to remove the oil drain plug.




5. Use the J 26941 and the J 23907 in order to remove the slip yoke oil seal.
6. Remove the gasket material from the housing.

Mainshaft and Synchronizers

Cleaning and Inspection Procedure

Important: Do not spin dry the ball bearings.

1. Clean all of the parts in a suitable solvent.
2. Air dry the parts.
3. Inspect the gears for the following conditions:
- Cracks
- Nicks
- Chipped gear teeth
- High spots (small shiny spots on the gear teeth mating surface). High spots could cause gear noise.
3. Inspect the other surfaces on the gears (such as the thrust faces and the bearing surfaces diameters).
4. Inspect the synchronizer sleeves for a sliding fit on the synchronizer hubs.
(Used output shaft hubs will have a slip fit.)
5. Inspect the synchronizer springs and keys for damage.
6. Inspect the synchronizer rings for excess wear.
7. Inspect the synchronizer clutching teeth for the following conditions:
- Wear
- Scuffing
- Nicks
- Burred or broken teeth
8. Inspect the speed gear clutching cones for metal transfer from the synchronizer ring.
9. Inspect the gear teeth for excessive wear.
10. Inspect the bearings and the bearing surfaces for the following conditions:
- Nicks
- Burrs
- Bent cages
- Wear
11. Lubricate all of the bearings. Check all of the bearings for rough rotation.
12. Use a soft stone or a crocus cloth in order to correct the following conditions:
(If a soft stone or crocus cloth cannot remove the condition, replace the component and inspect the mating parts.)
- Scuffs
- Nicks
- Burrs
- Scores
- Synchronizer ring metal transfers
13. Lubricate all of the components as assembly progresses.
Use lubricant Synchromesh Transmission Fluid with friction modifier GM P/N 12377916 or equivalent.

Input Shift Bearing Retainer Assembly

Tools Required
- J 23907 Slide Hammer With Adapter
- J 29369-2 Input Shaft Oil Seal Remover

1. Remove the rubber seal lip in order to expose the metal lip around the seal. Use pliers in order to remove the rubber seal lip.
2. Install the J 29369-2 below the metal lip of the seal.
3. Finger tighten the seal.
4. Turn the seal five additional turns.
5. Install the J 23907 and the J 29369-2 in order to remove the slip yoke oil seal.
6. Remove the retainer oil seal from the retainer.
7. Clean the gasket material from the retainer.
5. Inspect the shaft bearing retainer for wear or damage.

Rear Housing Assemble

Tools Required
- J 36190 Drive Handle
- J 36504 Output Shaft Oil Seal Installer
- J 36511 Oil Plug Hex Bit (17 mm)




1. Use the J 36190 in order to install the rear housing shift shaft bushing into the rear housing.
1. Install the bushing into the bore so that the writing on the bushing lip faces toward the housing
2. Install the bushing flush.




2. Install the shift shaft support and the snap ring into the rear housing.
3. Apply petroleum jelly between the lips of the seal.




4. Use the J 36504 in order to install the slip yoke oil seal.
5. Apply pipe sealant to the threads of the oil drain plug.




6. Use the J 36511 in order to install the oil drain plug.
Tighten
Tighten the oil drain plug to 37 N.m (27 lb ft).

Front Housing Assemble

Tools Required
- J 36190 Drive Handle
- J 36511 Oil Plug Hex Bit (17 mm)
- J 36798 Shift Shaft Bushing Adapter




1. Use the J 36798 and the J 36190 in order to install the shift shaft front housing bushings. Do not align the bushing split line with the hydro lock keyhole in the front housing.
2. Use the J 36511 to install the oil fill plug.

Reverse Idler Gear Assembly

1. Clean all of the parts in a suitable solvent.
Air dry the parts.
2. Inspect the gear teeth for the following conditions:
- Scuffs
- Nicks
- Burrs
- Breaks
- High spots (small shiny spots on the gear teeth mating surface). High spots could cause gear noise.
3. Inspect the bearing assembly for the following conditions:
(Replace if these conditions exist.)
- Roughness of rotation
- Burrs
- Pits
- Cage damage
4. Inspect the shaft for the following conditions:
- Scoring
- Wear
- Overheating
5. Use a soft stone or a crocus cloth in order to remove scuffs, nicks and burrs If these conditions cannot be removed, replace the component.
6. Inspect the O-rings for the following conditions:
- Cracks
- Splits
- Deformation

Transmission Assemble

Tools Required
- J 22873 Slide Hammer
- J 36183 Input Shaft Press Tube With Cap
- J 36184 Input Shaft Press Tube Reducer
- J 36511 Oil Fill Plug Hex Bit (17 mm) J 41663 Assembly Pallet Main Shaft Adapter

Notice: All synchronizer blocking rings found inside the transmission are interchangeable except those used on the reverse synchronizer.

Important: Install the synchronizer sleeves with the offset teeth toward the second, third and fifth gear.

Sleeves are identified with the following marks:
- First and second: One groove on the outer diameter (OD) of the first gear
- Third and fourth: Two grooves on the outer diameter (OD) of the third gear
- Fifth and reverse: Two grooves on the outer diameter (OD) of the fifth gear One groove on the reverse gear

Important: Lubricate all components during assembly.

Use lubricant Synchromesh Transmission Fluid with friction modifier GM P/N 12377916 or equivalent.
1. Position the following components onto the end of the output shaft:
1. The reverse gear
2. The synchronizer blocking ring
3. The fifth reverse synchronizer
Use the J 22873 in order to install the fifth reverse synchronizer.
4. The synchronizer blocking ring
5. The snap ring
6. The fifth gear




2. Use the J 22873 in order to install the ball bearing.
3. Install the snap ring to the mainshaft.
4. Position the speed sensor gear down the main shaft two inches from the ball bearing.
5. Use the J 22873 in order to position the ball bearing.




6. Position the following components onto the input end of the main shaft:
7. (Make sure that the scribed hub is correctly aligned.)
1. The first gear
2. The inner cone
3. The middle cone
4. The two synchronizer blocking rings
5. The first and second gear synchronizer
6. The first and second gear synchronizer hub
Align the synchronizer rings with the keys on the first and second gear synchronizer. One synchronizer ring should be on each side of the synchronizer and the hub.
7. Position the snap ring into the slot on the main shaft.




8. Position the following components onto the input end of the main shaft:
1. The middle cone
2. The inner cone
3. The second gear
4. The two piece split washer with the retainer ring.




9. Install the third gear.
10. Use the J 22873 in order to position the following components:
1. Two synchronizer blocking rings
2. The third and fourth gear synchronizer
3. The third and fourth gear synchronizer hub
11. Align the synchronizer blocking rings with the keys on the third and fourth gear synchronizer.
12. Position the snap ring.




13. Position the following components onto the input end of the main shaft:
1. The pocket bearing
2. The input shaft
14. Turn over the main shaft.
Reposition the main shaft onto the J 41663.
15. Press the counter shaft rear bearing onto the counter shaft.
16. Press the snap ring on to the counter shaft.




17. Position the counter shaft onto the J 41663.
- When assembling the reverse idler gear, make sure that the chamfer on the segment and the collar are facing up, toward the rear.
- Make sure that the groove on the idler gear is toward the collar.
18. Position the following components onto the reverse idler shaft:
1. The two O-rings
2. The caged roller bearings
3. The reverse idler gear
4. The idler shaft support collar
19. Position the reverse idler shaft assembly onto the J 41663.




20. Position the output shaft bearing retainer onto the mainshaft and the countershaft.
21. Make sure that the output shaft bearing retainer is positioned behind the ball bearings on the mainshaft and the countershaft.
22. Make sure that the fork end of the output shaft bearing retainer is positioned under the counter shaft ball bearing.
23. Make sure that the hook end of the output shaft bearing retainer is positioned under the main shaft ball bearing.




24. Install the fifth/reverse shift fork onto the first/second shift fork.
25. Install the fork assemblies onto the first/second and fifth/reverse gear sleeves.
26. Position the rear housing over the mainshaft, countershaft and reverse idler shaft assembly.




Important: Two bolts of different length are used to secure the idler shaft segment to the rear housing. The forward (front) reverse idler shaft assembly hole houses the short bolt.

27. Install the two bolts that secure the reverse idler shaft assembly to the rear housing. Finger tighten the two bolts.

Important:
- Use new O-rings with the five output shaft bearing retainer to housing bolts.
- Position the five new O-rings under the heads of the five output shaft to bearing retainer bolts prior to bolt installation.

28. Position the five bolts and the O-rings that secure the rear housing to the output shaft bearing retainer.




29. Connect the five output shaft bearing bolts in the following sequence:
1. Finger start bolts 1, 2, and 4.
2. Finger start bolts 3 and 5.
3. Finger tighten the bolts in the following order: 1,2,3,4,5.
4. Tighten the five output shaft bearing retainer to housing bolts in the following order: 1, 2, 3, 4, 5.
Tighten
Tighten the bolts to 22 N.m (16 lb ft).
5. Re-tighten the five output shaft bearing retainer to housing bolts in the following order: 1, 2, 3, 4, 5.
Tighten
Tighten the bolts to 22 N.m (16 lb ft).
6. Tighten the reverse idler shaft assembly to housing rear bolt.
Tighten
Tighten the reverse idler shaft assembly to housing rear bolt to 22 N.m (16 lb ft).
7. Tighten the reverse idler shaft assembly to housing forward bolt.
Tighten
Tighten the reverse idler shaft assembly to housing forward bolt to 44 N.m (33 lb ft).
30. Remove the rear housing assembly from the J 41663. Place the rear housing assembly horizontally.




31. Install the third/fourth fork onto the third and fourth gear synchronizer sleeve.
32. Install the following components onto the rear housing:
- The shift shaft bushing
- The shift shaft lever
- The shift shaft socket
33. Install the shift shaft through the following components:
- The third/fourth gear fork
- The shift shaft bushing
- The shift shaft lever
- The first/second shift fork
- The fifth/reverse shift fork
Place the shift shaft into the rear housing.
Push the shift shaft down when installing it into the rear housing.




34. Install the 22 mm (0.866 in) shift shaft lever roll pin into the shift shaft lever. Make sure that the roll pin to set flush with the shift shaft lever assembly.
35. Install the shift shaft socket and the 30 mm (1.18 in) roll pin onto the shift shaft. Make sure that the shift shaft socket roll pin is flush with the shift shaft socket hole.




36. Install the shift shaft spring and plunger assembly into the shift shaft lever assembly.

Important: The transmission must be in the 3rd or 4th gear position during the installation of the shift tower.

After the shift tower has been installed to the transmission, the shifter can be engaged into other shift positions.
37. Position the transmission into the third gear:
1. Center the shift shaft.
2. Push the shift shaft all the way to the rear of the rear housing.
38. Apply Loctite� 518 sealant to the mating surfaces of the rear housing.
39. Use the J 36183 and the J 36184 in order to install the input shaft ball bearing into the front housing.
40. Install the front counter shaft roller bearing into the front housing with petrolatum. Make sure that the small end of the counter shaft bearing is toward the front housing.




41. Position the front housing onto the rear housing.




42. Install the shift shaft detent blockout bushing pin into the top of the front housing.
Install the shift shaft detent blockout bushing pin by hand in order to ensure that the detent lock pin installs into the shift shaft lever and the shift shaft bushing.




43. Install the nine bolts which secure the front housing to the rear housing.
Tighten
- Tighten the nine housing bolts to 33 N.m (24 lb ft).
- Tighten the shift shaft detent blockout bushing pin to 33 N.m (24 lb ft).




44. Install the following components:
- The shift shaft detent plunger (1)
- The spring (2)
- The detent plug (3)




45. Install the snap ring on the input shaft front ball bearing.
46. Apply RTV sealant to the mating surfaces of the input shaft bearing retainer. Install the input shaft bearing retainer to the front housing.
47. Install the five bolts that secure the input shaft bearing retainer to the front housing.
Tighten
Tighten the bolts that secure the input bearing retainer to 29 N.m (21 lb ft).
48. Install the backup light switch into the rear housing.
Tighten
Tighten the backup light switch to 37 N.m (28 lb ft).
49. Add transmission oil. Refer to Manual Transmission Fluid.
Fluid - M/T





50. Use the J 36511 to install the oil fill plug.
Tighten
Tighten the oil fill plug to 23 N.m (17 lb ft).