GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • J 36601 Pinion Shim Selector
    • J 29763 Static Timing Gage
  1. Install the pinion bearing cups into the differential carrier assembly. Refer to Front Differential Drive Pinion Gear Bearing Cup Installation.
  2. Note: Make sure all of the tools, the pinion bearings, and the pinion bearing cups are clean before proceeding.

  3. Before assembly, lubricate the pinion bearings with axle lubricant. Use the correct fluid. Refer to Adhesives, Fluids, Lubricants, and Sealers.

  4. Object Number: 864965  Size: SH

    Note: The J 36601 uses two different measuring arms to measure the pinion depth. The J 36601-4 is used to measure the pinion depth for the 8.25 inch axle and the J 36601-3 is used to measure the pinion depth for the 9.25 inch axle.

  5. Install the J 36601-4 or the J 36601-3 (4) to the J 36601-7 (1).
  6. Install the J 21777-35 for the 8.25 inch axle or the J 21777-8 for the 9.25 inch axle (3) to the J 36601-7 (1).
  7. Install the inner pinion bearing into the differential carrier case half.
  8. Insert the J 36601-7 (1) with the J 21777-35 or the J 21777-8 (3) through the inner pinion bearing and the differential carrier case half.
  9. Install the outer pinion bearing.
  10. Note: Each end of the J 36601-5 is sized specifically for the 8.25 inch or the 9.25 inch outer pinion bearing. Ensure the correct end is being used when installing the J 36601-5 into the outer pinion bearing.

  11. While holding the outer pinion bearing in position, install the J 36601-5 (2), the washer, and the nut to the J 36601-7 (1).
  12. Caution: Refer to Fastener Caution in the Preface section.

  13. While holding the J 36601-7 (1) stationary with a wrench, tighten the nut on the J 36601-7 (1).
  14. Tighten
    Tighten the nut until all of the end play is removed from the J 36601 .

  15. Rotate the assembly several times in both directions in order to seat the pinion bearings.
  16. While holding the J 36601-4 or the J 36601-3 (4) stationary, measure the rotating torque of the J 36601 using an inch-pound torque wrench.
  17. Specification
    The rotating torque of the J 36601 should be between 1.1-2.3 N·m (10-20 lb in).

  18. If the torque is less than 1.0 N·m (10 lb in), continue to tighten the nut on the J 36601-7 until a rotating torque of 1.1-2.3 N·m (10-20 lb in) is obtained.

  19. Object Number: 864970  Size: SH
  20. Install the adjustment screw and the lock nut of the J 29763  (2) to the J 36601-4 or the J 36601-3.
  21. Install the J 29763 to the adjustment screw and lock nut assembly.
  22. Tighten the lock nut to hold the J 29763 in place.

    Note: The left side differential bearing adjuster assembly on the 9.25 inch axle must be removed prior to placing the J 36601-3 in the differential side bearing bore.

  23. Place the contact pad of the J 36601-4 or to the J 36601-3 into the differential side bearing bore.
  24. Adjust the J 29763 to the differential bearing bore by doing the following:
  25. 16.1. Loosen the lock nut on the J 29763 .
    16.2. Place the contact pad of the J 36601-4 or the J 36601-3 onto the differential side bearing bore.
    16.3. With the contact pad of the J 36601-4 or the J 36601-3 touching the differential side bearing bore, push down on the J 29763 until the needle of the J 29763 has turned 3/4 of a turn clockwise.
    16.4. Tighten the lock nut of the J 29763 .
  26. Rotate the J 36601-4 or the J 36601-3 (1) back and forth until the needle of the J 29763  (2) indicates the lowest point in the differential side bearing bore.
  27. At the lowest point of deflection, move the housing of the J 29763 until the needle indicates ZERO.
  28. Move the J 36601-4 or the J 36601-3 back and forth again to verify the zero setting. Adjust the housing of the J 29763 as necessary to set the needle to ZERO.

  29. Object Number: 864974  Size: SH
  30. After the ZERO setting is obtained and verified, grasp the J 36601-4 or the J 36601-3 (1) by the flats and move the J 36601-4 or the J 36601-3 out of the differential side bearing bore.
  31. Note: The unit of measurement for the J 29763 is in hundredths of a millimeter.

  32. The value indicated on the J 29763  (2) is the thickness of the shim needed in order to set the depth of the pinion.
  33. Select the shim that indicates the correct thickness. Measure the shim with a micrometer in order to verify that the thickness is correct.
  34. Remove the pinion depth setting tools.
  35. Remove the pinion bearings.
  36. Install the pinion shim between the drive pinion and the inner pinion bearing and assemble the differential carrier. Refer to Differential Carrier Assembly Assemble.

Differential pinion gear shims are available in the following sizes:

Shim Sizes

8.25 Inch Axle

9.25 Inch Axle

0.508 mm (0.020 in)

0.5131 mm (0.0202 in)

0.533 mm (0.021 in)

0.5395 mm (0.0212 in)

0.559 mm (0.022 in)

0.5639 mm (0.0222 in)

0.584 mm (0.023 in)

0.5893 mm (0.0232 in)

0.610 mm (0.024 in)

0.6147 mm (0.0242 in)

0.635 mm (0.025 in)

0.6401 mm (0.0252 in)

0.660 mm (0.026 in)

0.6655 mm (0.0262 in)

0.686 mm (0.027 in)

0.6909 mm (0.0272 in)

0.711 mm (0.028 in)

0.7163 mm (0.0282 in)

0.737 mm (0.029 in)

0.7417 mm (0.0292 in)

0.762 mm (0.030 in)

0.7671 mm (0.0302 in)

0.787 mm (0.031 in)

0.7925 mm (0.0312 in)

0.813 mm (0.032 in)

0.8179 mm (0.0322 in)

0.838 mm (0.033 in)

0.8433 mm (0.0332 in)

0.864 mm (0.034 in)

0.8687 mm (0.0342 in)

0.889 mm (0.035 in)

0.8941 mm (0.0352 in)

0.914 mm (0.036 in)

0.9195 mm (0.0362 in)

0.940 mm (0.037 in)

0.9449 mm (0.0372 in)

0.965 mm (0.038 in)

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0.991 mm (0.039 in)

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1.016 mm (0.040 in)

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1.041 mm (0.041 in)

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1.067 mm (0.042 in)

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1.092 mm (0.043 in)

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1.118 mm (0.044 in)

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1.143 mm (0.045 in)

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1.168 mm (0.046 in)

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1.194 mm (0.047 in)

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1.219 mm (0.048 in)

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1.245 mm (0.049 in)

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1.270 mm (0.050 in)

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