GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • J 8001 Dial Indicator Set
    • J 39444-1 Countershaft End Play Rod
        For equivalent regional tools, refer to Special Tools.

Note: The shimming procedure is required to be performed during service only when the following parts are replaced:

   • The input shaft
   • The counter shaft
   • The main shaft
   • The adapter plate
   • The main housing
   • The extension housing

Input Shaft, Mainshaft, and Countershaft


    Object Number: 1938464  Size: SH
  1. Rotate the transmission adapter plate to the vertical position.
  2. Install the following assemblies in order:
  3. 2.1. The input shaft to the adapter plate
    2.2. Align the 4th speed gear blocking ring to the input shaft.
    2.3. The mainshaft assembly

            Note: Lift up the mainshaft enough to install the countershaft.

    2.4. The countershaft

    Object Number: 1938466  Size: SH
  4. Install the transmission case.
  5. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1938467  Size: SH
  6. Install the adapter plate to transmission case bolts and tighten to 36 N·m (27 Ib ft).

  7. Object Number: 1938468  Size: SH
  8. Measure the input shaft/mainshaft end play using the following procedure:
  9. 5.1. Place the tip of the J 8001 indicator set -3 on the end of the mainshaft.
    5.2. Move the main shaft up and down.
    5.3. Record the measurement.
  10. Select a shim to achieve 0.0127-0.0889 mm (0.00049-0.00349 in) preload.
  11. Remove the J 8001 indicator set -3.

  12. Object Number: 1847550  Size: SH
  13. Measure the countershaft end play using the following procedure:
  14. 8.1. Place the tip of the J 8001 indicator set -3 on the end of the countershaft.
    8.2. Move the countershaft up and down.
    8.3. Record the measurement.
  15. Select a shim to achieve 0.0127-0.0889 mm (0.00049-0.00349 in) preload.
  16. Remove the J 8001 indicator set -3.

  17. Object Number: 1938470  Size: SH
  18. Remove the shift lever guide bolts.

  19. Object Number: 1938467  Size: SH
  20. Remove the adapter plate to the transmission case bolts.

  21. Object Number: 1938466  Size: SH
  22. Remove the transmission case.

  23. Object Number: 1938464  Size: SH
  24. Remove the following parts in order:
  25.         Note: Lift up the mainshaft enough to remove the countershaft.

    14.1. The countershaft
    14.2. The mainshaft assembly
    14.3. The input shaft from the adapter plate

    Object Number: 1938473  Size: SH
  26. Remove the input shaft bearing race.
  27. Remove the input shaft bearing shim and discard.
  28. Install the new input shaft bearing shim, and the original bearing race.

  29. Object Number: 1938474  Size: SH
  30. Remove the countershaft bearing race.
  31. Remove the countershaft bearing shim and discard.
  32. Install the new input shaft bearing shim, and the original bearing race.
  33. Refer to Transmission Assemble.