Gear Tooth Contact Pattern Check

TOOTH CONTACT PATTERN TEST

^ 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.
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 the J 39446
Attach the exciter ring protector to the speed sensor reluctor wheel on vehicles with non-traction control rear axles only.
6. Use a medium stiff brush in order to apply a mixture of gear marking compound sparingly to all of the ring gear teeth.
Visibility of the area of the differential drive pinion gear contact identifies proper usage when a hand load is applied.

7. Tighten the differential carrier bearing cap bolts/screws.
^ Tighten the differential carrier bearing cap bolts/screw to 75 Nm (55 ft. lbs.).

NOTICE: Refer to Fastener Notice in Service Precautions.

8. Apply the park brake until a torque of 54 - 70 Nm (40 -52 ft. lbs.) is required in order to turn the drive pinion gear (16 or 14).

IMPORTANT: A test made without loading the gears will not give a satisfactory pattern.

9. Use the following procedure in order to obtain a ring gear tooth contact pattern:
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.

10. Inspect the differential ring gear teeth for a low flank contact pattern (2).
11. Decrease the differential drive pinion gear bearing shim thickness in order to repair low flank contact if a low flank contact pattern (2) exists.
Decreasing the differential drive pinion gear shim thickness moves the smaller diameter of the differential drive pinion gear contact (2) out toward the differential ring gear center line (1).

12. Inspect the differential ring gear teeth for a heel contact pattern (1).
13. Decrease the backlash in order to repair heel contact if a heel contact pattern (1) exists.
Decreasing the backlash moves the area of differential drive pinion gear contact (1) toward the toe.





14. Inspect the differential ring gear teeth for a high face contact pattern (2).





15. Increase the differential drive pinion gear bearing shim thickness in order to repair high face contact if a high face contact pattern (2) exists.
Increasing the differential drive pinion gear shim thickness moves the area of differential drive pinion gear contact (2) out toward the differential ring gear center line (1).





16. Inspect the differential ring gear teeth for a toe contact pattern (1).
17. Increase the backlash in order to repair heel contact if a toe contact pattern (1) exists.
Increasing the backlash moves the area of differential drive pinion gear contact (1) toward the heel.





18. Inspect the differential ring gear teeth for a desired tooth contact pattern (1).
19. Verify that the area of differential drive pinion gear contact (1) remains in the center of the differential ring gear tooth.
20. If the differential ring gear tooth pattern is acceptable, remove the J 39446.
21. Install the rear axle housing cover.