GM Service Manual Online
For 1990-2009 cars only

Mainshaft

Tools Required

    • J 36513 Split Plate
    • J 39442 Press Adapter
    • J 39443 Split Plate
    • J 39473 Mainshaft Bearing Installer

    Object Number: 105701  Size: SH

    Important: Measure the 4th speed gear synchronizer wear gap before disassembling the mainshaft.

  1. Install the input shaft in the adapter plate.
  2. Install the mainshaft on the input shaft.
  3. Using a feeler gauge measure the gap between the 4th speed gear blocking ring and the 4th speed gear.
  4. Replace the 4th speed gear friction cone and blocking ring when the gap is less than 1.27 mm (0.050 in).
  5. Notice: Do not overtighten the J 36513 split plate past the gear teeth or damage to gear may occur.

  6. Using the J 36513 , close the split plate only enough to support the gear teeth, and the J 39442 , remove the following parts in order:
  7. 5.1. If an O-ring is present on the mainshaft, remove and discard the O-ring. The O-ring was used for manufacturing purposes only.
    5.2. The mainshaft large tapered bearing
    5.3. The 1st speed gear
    5.4. The 1st speed gear caged needle bearing
    5.5. The 1st speed bearing spacer

    Object Number: 105686  Size: SH
  8. Remove the following parts in order:
  9. 6.1. The 1st speed gear inner cone
    6.2. The 1st speed gear friction cone
    6.3. The 1st speed gear blocking ring
    6.4. The retainer ring

    Object Number: 4810  Size: SH

    Important: The synchronizer hubs and sliding sleeves are a selected assembly. Keep these parts together as originally assembled.

  10. Scribe a mark on the synchronizer hub and on the sleeve. This will help you to reinstall the parts in the same position.

  11. Object Number: 388449  Size: SH
  12. Remove the 2nd speed gear. The 1st/2nd speed synchronizer assembly, the 2nd speed gear blocking ring, the 2nd speed gear friction cone, and the 2nd speed gear inner cone will press off with the 2nd speed gear. Use the J 36513 in an inverted position, J 39442 and a hydraulic press.

  13. Object Number: 105698  Size: SH
  14. Remove the 2nd speed gear spacer and caged needle bearing.

  15. Object Number: 38328  Size: SH
  16. Remove the mainshaft small tapered bearing. Use the J 39442 , the J 39443 , and a hydraulic press.
  17. Discard the small tapered bearing.

  18. Object Number: 388451  Size: SH
  19. Remove the following parts in order:
  20. 12.1. Retainer
    12.2. 4th gear thrust washer
    12.3. 4th gear inner cone
    12.4. 4th gear friction cone
    12.5. 4th gear blocking ring

    Object Number: 4810  Size: SH

    Important: The synchronizer hubs and sliding sleeves are a selected assembly. Keep these parts together as originally assembled.

  21. Scribe a mark on the synchronizer hub and on the sleeve. This will help you to reinstall the parts in the same position.

  22. Object Number: 388453  Size: SH
  23. Use the J 39473 , V-blocks, and a hydraulic press to remove the 3rd speed gear. The 3rd/4th speed synchronizer assembly, the 3rd speed gear blocking ring, the 3rd speed gear friction cone, the 3rd speed gear inner cone, thrust washer, and spacer will press off with the 3rd speed gear.

  24. Object Number: 105693  Size: SH
  25. Remove the 3rd speed gear caged needle bearing.

Input Shaft

Tools Required

    • J 22912-O1 Split Plate
    • J 23907 Slide Hammer
    • J 39594 Bearing Race Remover

    Important: Do not replace the tapered bearing or the bearing race unless inspection shows that the bearing or the race are damaged.


    Object Number: 105682  Size: SH
  1. Remove the tapered bearing from the input shaft, using the J 22912-O1 and a hydraulic press.

  2. Object Number: 105684  Size: SH
  3. Remove the bearing race from the input shaft, using the J 23907 and the J 39594 .