GM Service Manual Online
For 1990-2009 cars only

Input Shaft, Mainshaft, and Countershaft

Tools Required

    • J 8001 Dial Indicator Set
    • J 39444-1 Countershaft End Play Rod
  1. Lubricate all components as assembly progresses, using J 36850 .

  2. Object Number: 1955724  Size: SH
  3. Install the input shaft (1) in the adapter plate (2).

  4. Object Number: 1955715  Size: SH
  5. Assemble the shift shaft (2) to the mainshaft (1).
  6. Install the neutral return roll pin (3) to the shift shaft (2).
  7. Install the mainshaft (1) and the shift shaft (2) assembly into the adapter plate (3).

  8. Object Number: 1956971  Size: SH
  9. Install the countershaft assembly (1) to the adapter plate (3) using the following sequence:
  10. 6.1. Lift up the mainshaft assembly (2) enough in order to install the countershaft assembly (1).
    6.2. Install the countershaft assembly (1).
    6.3. Lift the mainshaft assembly (2) enough in order to rotate the input shaft to engage the synchronizer keys with 4th gear blocking ring.

    Object Number: 1955708  Size: SH
  11. Install the transmission case (1).

  12. Object Number: 1956967  Size: SH
  13. Install the adapter plate to transmission case bolts (1).
  14. Tighten
    Tighten the bolts to 48 N·m (36 Ib ft).


    Object Number: 1956980  Size: SH
  15. Measure the input shaft/mainshaft end play using the following procedure:
  16. 9.1. Place the tip of the J 8001 on the end of the mainshaft.
    9.2. Move the input shaft up and down.
    9.3. Record the measurement.
  17. Select a shim to achieve 0.00-0.05 mm (0.000-0.002 in) preload.
  18. Remove the J 8001 .

  19. Object Number: 1956982  Size: SH
  20. Remove the adapter plate plug (1).

  21. Object Number: 1956981  Size: SH
  22. Place the tip of the J 8001 on the end of the countershaft.
  23. Measure the countershaft end play using the following procedure:
  24. 14.1. Install the J 39444-1 through the adapter plate plug hole. Screw the J 39444-1 into the countershaft.
    14.2. Move the countershaft up and down with the countershaft end play rod J 39444-1 .
    14.3. Record the measurement.
  25. Select a shim to achieve 0.00-0.05 mm (0.000-0.002 in) preload.
  26. Remove the J 8001 .
  27. Remove the J 39444-1 .

  28. Object Number: 1956968  Size: SH
  29. Remove the adapter plate to transmission case bolts (2).
  30. Remove the shift lever guide bolts (1).

  31. Object Number: 1955708  Size: SH
  32. Remove the transmission case (1).

  33. Object Number: 1956971  Size: SH
  34. Remove the countershaft (1) from the adapter plate (3). Lift up the mainshaft (2) enough in order to remove the countershaft (1).

  35. Object Number: 1955715  Size: SH
  36. Remove the mainshaft and the shift shaft components as an assembly (1) from the adapter plate.
  37. Important: When removing the shift shaft be careful not to lose the dowel pin.

  38. Remove the shift shaft assembly from the mainshaft.

  39. Object Number: 1955724  Size: SH
  40. Remove the input shaft (1) from the adapter plate (2).

Countershaft

Tools Required

    • J 8001 Dial Indicator Set
    • J 39444-2 Countershaft End Play Rod

Important: The following procedure cannot be performed accurately until the countershaft shimming procedure has been completed.

  1. Rotate the transmission in the horizontal position.

  2. Object Number: 1956993  Size: SH

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

  3. Install the extension housing (2).
  4. Install the extension housing bolts (1).
  5. Tighten
    Tighten the bolts to 48 N·m (36 lb ft).


    Object Number: 1956982  Size: SH
  6. Remove the adapter plate plug (1).

  7. Object Number: 38428  Size: SH
  8. Measure the countershaft end play using the following procedure:
  9. 5.1. Install a J 8001 so the tip is on the end of the countershaft end play rod.
    5.2. Rotate the transmission in the vertical position.
    5.3. Move the countershaft up and down using the J 39444-2 .
    5.4. Record the measurement.
  10. Select a shim to achieve 0.05-0.13 mm (0.002-0.005 in) axial play.
  11. Remove the J 8001 .
  12. Remove the J 39444-2 .

  13. Object Number: 1956982  Size: SH
  14. Install the adapter plate plug (1).
  15. Tighten
    Tighten the plug to 27 N·m (20 Ib ft).