Differential Assembly & Adjustment

Ring gear should be removed for preliminary side bearing preload adjustment.
1. Lubricate differential case side bearings, mount outer race over each bearing and install case assembly in housing.
2. On models with 8-7/8 inch ring gear, insert 0.080 inch thick shim between each side bearing race and housing.
3. On models with 7-9/16 inch ring gear, insert 0.142 inch thick shim between each bearing race and housing.
4. On all models, install bearing caps and tighten bolts hand tight.

Fig. 6 Side Bearing Endplay Measurement:

5. Mount suitable dial indicator on housing with plunger contact bearing against ring gear mounting flange.
6. Insert suitable lever between shim and housing, firmly pry case assembly to one side, then zero dial indicator. Do not zero or read indicator while prying case assembly.
7. Firmly pry case assembly to opposite side, then record indicator reading.
8. Repeat steps 6 and 7 several times to ensure accurate reading. Dial indicator reading is the amount that must be added to shim thickness to obtain zero side bearing endplay and zero preload.
9. Select 2 shims, as close to equal thickness as possible, with thickness of each shim equal to thickness of preliminary shim plus one-half of indicator reading obtained in steps 6 through 8.
10. Remove differential case assembly and install ring gear.
11. Reinstall differential case assembly along with side bearing outer races, and insert shims selected in step 9 between bearing races and housing.
12. Install bearing caps and evenly torque cap bolts to 87 ft. lbs. on models with 8-7/8 inch ring gear or 57 ft. lbs. on models with 7-9/16 inch gear.

Fig. 7 Ring Gear & Backlash Measurement:

13. Mount suitable dial indicator on housing with plunger at right angle to ring gear tooth and contact against tooth.
14. Hold pinion and rock ring gear back and forth, reading backlash from dial indicator.
15. If backlash is not within specifications, adjust as follows:
a. If backlash is greater than specified, increase thickness of shim on back side of ring gear and decrease thickness of shim on tooth side of gear by an equal amount.
b. If backlash is less than specified, increase thickness of shim on ring gear tooth side and decrease thickness of opposite shim by an equal amount. Total shim thickness must remain constant when adjusting backlash in order to maintain side bearing preload at zero.
16. When backlash has been properly adjusted, remove dial indicator, differential case assembly and side bearing shims, keeping all components in order.
17. Measure thickness of each side bearing shim pack and select shims that are 0.004 inch thicker than each shim pack. Adding 0.004 inch to each shim pack will provide the specified, 0.008 inch increase from zero preload while maintaining specified ring gear and pinion backlash.
18. Install selected shim packs in respective sides of axle housing.
19. Place outer races over side bearings and position differential assembly in housing so that bearings just begin to enter bores.
20. Evenly tap outer edge of side bearing races to seat differential in housing. Care must be taken not to damage shims or bearings when installing differential assembly.
21. Install bearing caps and evenly torque bolts to 87 ft. lbs. on models with 8-7/8 inch ring gear or 57 ft. lbs. on models with 7-9/16 inch gear.
22. Check ring gear and pinion tooth contact using suitable marking compound, and correct adjustment as needed to obtain even, centered contact.
23. Install axle shafts as outlined in service section.
24. Install rear cover and new gasket, then fill axle with specified lubricant.