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.

Transmission Case Installation

Tools Required

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 12345739, (Canadian P/N 10953472) or equivalent to the transmission case to adapter plate mating surface.

  2. Object Number: 1385070  Size: SH
  3. Do the following in order to install the transmission case and the offset lever:
  4. 2.1. Shift the transmission into NEUTRAL in order to keep the 3rd/4th shift shaft from engaging.
    2.2. Install the offset lever.
    2.3. Slide the transmission case onto the gear clusters and the shift rail components.

    Object Number: 350592  Size: SH
  5. Apply threadlock GM P/N 12346004, (Canadian P/N 10953480) or equivalent to the threads of the shift lever guide bolts.

  6. Object Number: 1386561  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 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.
  8. Tighten
    Tighten the bolts to 27 N·m (20 Ib ft).


    Object Number: 1385067  Size: SH
  9. Install the adapter plate to transmission case bolts.
  10. Tighten
    Tighten the bolts to 48 N·m (36 Ib ft).


    Object Number: 1385069  Size: SH
  11. Install the magnets into the transmission case.

  12. Object Number: 1737057  Size: SH
  13. Install the shift detent roller, spring and plug.

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


    Object Number: 1385065  Size: SH
  17. Install the computer aided gear select solenoid.
  18. 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: 1737054  Size: SH
  4. Install the reverse shift collar and reverse shift collar pin.

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

    Object Number: 1718918  Size: SH
  5. Install the following parts in order:
  6. • The snap ring
    • The speed sensor rotor
    • The snap ring

    Object Number: 1385064  Size: SH
  7. Install the shift shaft extension.
  8. Install the shift guide.
  9. Install NEW shift guide roll pins.

  10. Object Number: 1737057  Size: SH
  11. Lift up on the shift shaft extension while installing the shift detent roller, spring and plug.

Extension Housing Assemble

Tools Required

J 39430 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 12345382, (Canadian P/N 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 12345739, (Canadian P/N 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 12346004, (Canadian P/N 10953480) or equivalent to the top 2 extension housing bolts.

  12. Object Number: 1385059  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).


    Object Number: 1385063  Size: SH
  16. Install the propshaft connector.
  17. Install the propshaft connector nut.
  18. Tighten
    For the CTS only, tighten the nut to 136 N·m (100 lb ft).


    Object Number: 1778953  Size: SH
  19. Install the shifter cover plate.
  20. Install the shifter cover plate bolts.
  21. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).

  22. Install the vent tube.

  23. Object Number: 1385057  Size: SH
  24. Remove the J 39430  (2).

  25. Object Number: 1385053  Size: SH
  26. Install the remaining 2 adapter plate bolts (1) and (2).
  27. Tighten
    Tighten the adapter plate bolts to 48 N·m (36 lb ft).