Side Bearing Preload Adjustment

Tool Required:
- J 22779 Side Bearing Backlash Gage

- The differential side bearing preload is adjusted by changing the thickness of the left and right shims equally. This will not change the original backlash.
- Production shims are cast iron and are not to be reused.
- Service spacer thickness is nominal at 4.32 mm (0.170 inch).
- Service shims are available from 1.02 mm to 2.54 mm (0.040 to 0.100 inch) in increments of 0.101 mm (0.004 inch).
- Make sure the side bearing surfaces are clean and free of burrs.

1. Place the differential case and the bearing cups into the axle housing.
A. Lubricate the axle bearings with axle lubricant.
B. Support the case to keep it from falling into the axle housing.
2. Install the strap from J 22779 on the left bearing with the cap bolts. Tighten the bolts snugly.
3. Push the ring gear towards the pinion.
- Engage the ring gear with the pinion tightly, to a backlash of 0.000 inch (No noticeable looseness).





4. Insert J 22779 between the axle housing and left bearing cup.





5. Move the tool back and forth in the bore while turning the adjusting nut clockwise until a noticeable drag is produced.
A. Tighten the lock bolt on the side of the tool.
B. Leave the tool in place.
6. Install a service spacer (9) and service shim (9) between the right bearing cup and axle housing.
7. Determine bearing preload by inserting progressively larger feeler gage sizes between the carrier and service shim.
- Push the feeler gage downward so it contacts the shim at the top and bottom and then contacts the axle housing.
- The point just before additional drag begins is the correct feeler gage thickness. This is the zero setting without preload.
8. Remove the strap, J 22779, the service spacer, service shim, feeler gage, and differential case from the axle housing.





9. Measure J 22779 in three places using a micrometer. Average the readings.
10. Add the dimensions of the right side service spacer, service shim, and feeler gage.
11. For an initial backlash setting, move the ring gear away from the pinion by subtracting 0.010 inch from the ring gear side shim pack and adding 0.010 inch to the shim pack on the opposite side.
12. To obtain the proper preload on the side bearings add 0.10 mm (0.004 inch) to the measurement of each shim pack.
13. Install the differential. Refer to BACKLASH ADJUSTMENT.