GM Service Manual Online
For 1990-2009 cars only

Shift Shaft Assemblies and Gear Clusters Installation

Tools Required

J 36850 Transjel® Lubricant Assembly Lube

  1. Lubricate all components as assembly progresses, using J 36850 .

  2. Object Number: 388448  Size: SH
  3. Install the input shaft in the adapter plate.

  4. Object Number: 388446  Size: SH
  5. Assemble the shift shaft to the mainshaft.
  6. Install the neutral return roll pin to the shift shaft.
  7. Install the mainshaft and the shift shaft assembly into the adapter plate.

  8. Object Number: 388442  Size: SH
  9. Install the countershaft assembly using the following sequence:
  10. 6.1. Lift up the mainshaft assembly enough in order to install the countershaft assembly.
    6.2. Install the countershaft assembly.
    6.3. Lift the mainshaft assembly enough in order to rotate the input shaft to engage the synchronizer keys with 4th gear blocking ring.

    Object Number: 388439  Size: SH
  11. Install the 5th/6th and the reverse shift shaft.
  12. Align the slots of the shift shaft levers with the interlock plate.

Reverse Lockout Assembly Assemble


    Object Number: 350562  Size: SH

    Caution: The reverse lockout assembly is under spring pressure. Exercise caution when removing the retainer ring, as bodily injury may result.

  1. Install the reverse lockout plunger (6).
  2. Install the reverse lockout outer spring (5).
  3. Install the reverse lockout collar (4).
  4. Compress the reverse lockout plunger and the collar (4) in a vise and Install the retainer ring (3).
  5. Install the reverse lockout inner spring (2).
  6. Install the reverse lockout components in the body (1).
  7. Install the retainer ring (7).
  8. Install the O-ring to body (8).

Transmission Case Installation

Tools Required

    • J 41099 Skip Shift Sensor Remover/Installer
    • J 36850 Transjel® Lubricant

    Object Number: 38403  Size: SH

    Important: Lubricate all components as the assembly progresses. Use J 36850 or the equivalent.

  1. Apply sealant GM P/N United States 12345739, GM P/N Canada 10953472 or equivalent to the transmission case to adapter plate mating surface.

  2. Object Number: 350591  Size: SH
  3. Install the ball detent and the spring in the front offset lever.

  4. Object Number: 388438  Size: SH
  5. Do the following in order to install the transmission case and the offset lever:
  6. 3.1. Shift the transmission into NEUTRAL in order to keep the 3rd/4th shift shaft from engaging.
    3.2. Install the offset lever.
    3.3. Compress the front offset lever together while sliding it onto the shift shaft. This will prevent the spring release of the inner components.
    3.4. Slide the transmission case onto the gear clusters and the shift rail components.

    Object Number: 350592  Size: SH
  7. Apply threadlock GM P/N United States 12346004, GM P/N Canada 10953480 or equivalent to the threads of the shift lever guide bolts.

  8. Object Number: 105691  Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  9. Install the shift lever guide bolts and pull up on 5th/6th and reverse shift rail assembly. This will help align the slot of the shift interlock plate with the guide bolt hole.
  10. Tighten
    Tighten the bolts to 27 N·m (20 Ib ft).


    Object Number: 105692  Size: SH
  11. Install the adapter plate to transmission case bolts.
  12. Tighten
    Tighten the bolts to 48 N·m (36 Ib ft).


    Object Number: 350556  Size: SH
  13. Install the magnets into the transmission case.

  14. Object Number: 350558  Size: SH
  15. Install the offset lever roll pin.

  16. Object Number: 388460  Size: SH
  17. Install the shift detent assembly.
  18. Tighten
    Tighten the detent assembly to 40 N·m (30 Ib ft).


    Object Number: 38411  Size: SH
  19. Apply sealant GM P/N United States 12345739, GM P/N Canada 10953472 or the equivalent to the mating surface of the cover plate.

  20. Object Number: 105689  Size: SH
  21. Install the transmission case cover and the case cover bolts.
  22. Tighten
    Tighten the bolts to 20 N·m (15 Ib ft).


    Object Number: 388457  Size: SH
  23. Install the reverse lockout body and bolt in the cover plate.
  24. Tighten
    Tighten the bolts to 18 N·m (13 Ib ft).


    Object Number: 71530  Size: SH
  25. Install the reverse lockout solenoid to reverse lockout body assembly, using the J 41099 .
  26. Tighten
    Tighten the solenoid to 40 N·m (30 Ib ft).


    Object Number: 350553  Size: SH
  27. Install the computer aided gear select solenoid.
  28. Tighten
    Tighten the solenoid to 40 N·m (30 Ib ft).

Countershaft Extension Installation


    Object Number: 388437  Size: SH
  1. Position the transmission in the horizontal position.
  2. Install the countershaft extension assembly and the 5th/6th shift fork. The splines of the countershaft extension must engage the splines of the countershaft.

  3. Object Number: 388434  Size: SH
  4. Install the 5th/6th shift fork retainer ring.

5th/6th Speed Driven Gear Installation

Tools Required

    • J 39441 5th/6th Driven Gear Installer
    • J 39441-10 5th Gear Installer Adapter

Object Number: 389848  Size: SH

Install the 5th/6th speed driven gear using the J 39441 and J 39441-10 . The smaller outside diameter (OD) of the gear faces down.

Reverse Shift Fork Installation


    Object Number: 388432  Size: SH
  1. Install the reverse shift fork, the synchronizer and the thrust washer.

  2. Object Number: 388431  Size: SH
  3. Install a new shift fork retainer ring.

  4. Object Number: 388430  Size: SH
  5. Install the reverse synchronizer retainer ring.

Reverse Speed Gear Installation


    Object Number: 38238  Size: SH
  1. Install the following parts in order:
  2. 1.1. The blocking ring
    1.2. The wave washer
    1.3. The wave washer so the concave side faces the blocking ring
    1.4. The caged needle bearing
    1.5. The reverse speed gear
    1.6. The thrust washer
    1.7. The retainer ring

    Object Number: 38233  Size: SH
  3. Install the following parts in order:
  4. 2.1. The spacer
    2.2. The roller bearing
    2.3. The spacer
    2.4. The roller bearing retainer ring

Extension Housing Assemble

Tools Required

J 44395 Transmission Holding Fixture


    Object Number: 38379  Size: SH
  1. Install the following parts in order:
  2. 1.1. The funnel
    1.2. The selective shims. Refer to the Countershaft Extension in Shimming Procedures .
    1.3. The countershaft extension bearing race

    Object Number: 105688  Size: SH
  3. Install the following parts in order:
  4. 2.1. The reverse idler shaft
    2.2. The roller bearing
    2.3. The reverse idler gear

    Object Number: 38712  Size: SH
  5. Apply GM P/N United States 12345382, GM P/N Canada 10953489 or the equivalent to the reverse idler shaft brackets bolt threads.

  6. Object Number: 38375  Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  7. Install the following parts in order:
  8. 4.1. The reverse idler shaft bracket.
    4.2. The reverse idler shaft bracket bolts.

    Tighten
    Tighten the bolts to 25 N·m (18 Ib ft).


    Object Number: 38416  Size: SH
  9. Apply sealant GM P/N United States 12345739, GM P/N Canada 10953472 or equivalent to the extension housing to the transmission case mating surface.

  10. Object Number: 38712  Size: SH
  11. Apply thread sealer GM P/N United States 12346004, GM P/N Canada 10953480 or equivalent to the top two extension housing bolts.

  12. Object Number: 74203  Size: SH

    Important: Align the 5th/6th shift shaft to the extension housing bore in order to install the extension housing.

  13. Install the extension housing.
  14. Install the extension housing bolts.
  15. Tighten
    Tighten the bolts to 48 N·m (36 lb ft).

  16. Install the vent tube.

  17. Object Number: 74206  Size: SH
  18. Remove the J 44395 .

  19. Object Number: 639703  Size: SH
  20. Install the remaining two adapter plate bolts (1) and (2).
  21. Tighten
    Tighten the adapter plate bolts to 48 N·m (36 lb ft).