GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39446 ABS Exciter Ring Protector Kit

    Notice: It is very important that tooth contact be tested after the differential is taken apart. Variations in the differential or differential drive pinion gear inner bearing may cause the differential drive pinion gear to be too far away from, or close to, the differential ring gear. Therefore, the tooth contact pattern must be tested and corrected, (if necessary) to prevent gear noise.

  1. Clean all of the dirt from the area of the rear axle housing cover before removing the rear axle housing cover.
  2. Remove the rear axle housing cover. Refer to Rear Axle Housing Cover and Gasket Replacement .
  3. Wipe the oil out of the rear axle housing.
  4. Carefully clean each tooth of the ring gear.
  5. Select the correct exciter ring protector from J 39446 .
  6. Attach the exciter ring protector to the speed sensor reluctor wheel on vehicles with non-traction control rear axles only.

  7. Using a medium stiff brush, apply a mixture of gear marking compound sparingly to all of the ring gear teeth. The area of tooth contact of the differential drive pinion gear should remain visible
  8. 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. Tighten the differential carrier bearing cap bolts/screws.
  10. Tighten
    Tighten the differential carrier bearing cap bolts/screw to 75 N·m (55 lb ft).

  11. Apply the park brake until a torque of 54-70 N·m (40-52 lb ft) is required in order to turn the drive pinion gear.
  12. Important: A test made without loading the gears will not give a satisfactory pattern.

  13. Use the following procedure in order to obtain a ring gear tooth contact pattern:
  14. 9.1. Turn the pinion gear yoke with a wrench so that the ring gear rotates one full revolution.
    9.2. Reverse the rotation so that the ring gear rotates one revolution in the opposite direction.

    Object Number: 180092  Size: SH
  15. Inspect the differential ring gear teeth for a tooth contact pattern (1).
  16. The pattern is acceptable if the area of differential drive pinion gear contact (1) remains in the center of the differential ring gear tooth. If the pattern is not acceptable, proceed to Step 14.
  17. If the differential ring gear tooth pattern is acceptable, remove J 39446 .
  18. Install the rear axle housing cover. Refer to Rear Axle Housing Cover and Gasket Replacement .

  19. Object Number: 180096  Size: SH
  20. Inspect the differential ring gear teeth for a low flank contact pattern (2).
  21. If this contact pattern (2) exists, repair the low flank contact by decreasing the shim thickness of the bearing on the differential drive pinion gear. This moves the smaller diameter of the contact (2) out toward the center line (1) of the differential ring gear.
  22. Remove J 39446 .
  23. Install the rear axle housing cover. Refer to Rear Axle Housing Cover and Gasket Replacement .

  24. Object Number: 180095  Size: SH
  25. Inspect the differential ring gear teeth for a heel contact pattern (1).
  26. If this contact pattern (1) exists, repair the heel contact by decreasing the backlash. This moves the area of differential drive pinion gear contact (1) toward the toe.
  27. Remove J 39446 .
  28. Install the rear axle housing cover. Refer to Rear Axle Housing Cover and Gasket Replacement .

  29. Object Number: 180094  Size: SH
  30. Inspect the differential ring gear teeth for a high face contact pattern (2).
  31. If this contact pattern (2) exists, repair the high face contact by increasing the thickness of the bearing shim of the differential drive pinion gear. This moves the area of differential drive pinion gear contact (2) out toward the differential ring gear center line (1).
  32. Remove J 39446 .
  33. Install the rear axle housing cover. Refer to Rear Axle Housing Cover and Gasket Replacement .

  34. Object Number: 180093  Size: SH
  35. Inspect the differential ring gear teeth for a toe contact pattern (1).
  36. If this contact pattern (1) exists repair the heel contact by Increasing the backlash. This moves the area of differential drive pinion gear contact (1) toward the heel.
  37. Remove J 39446 .
  38. Install the rear axle housing cover. Refer to Rear Axle Housing Cover and Gasket Replacement .