Differential Case: Service and Repair

Steps 1 through 4 apply to conventional type units only.
1. Install side gears and thrust spacers, and pinion gears and washers into differential case. Install side gear thrust washers with oil grooves facing side gears.
2. Install pinion shaft. Do not install lock pin at this time.
3. Adjust differential gear backlash as follows:
a. Insert a wedge between side gear and pinion shaft to prevent side gear from turning.

Fig. 6 Measuring differential gear backlash. Conquest:

b. Install suitable dial indicator to gear, and measure gear backlash.
c. If backlash exceeds specifications, install thicker side gear thrust spacers as needed, then recheck backlash.
4. Align pinion shaft lock pin hole with differential case lock pin hole and drive lock pin into place. Stake the lock pin in position in two places, using a suitable punch.
5. On limited slip type units, adjust clearance between clutch plate and differential case when installing internal components as follows:

Fig. 7 Measuring differential case depth. Limited slip differential:

a. "A" = E - F + G.

Fig. 8 Measuring preload spring thickness. Limited slip differential:

b. Measure thickness of preload spring. The total thickness of both springs will be considered as value "L".

Fig. 9 Measuring pinion shaft & clutch plate assembly width. Limited slip differential:

c. Assemble pinion shaft holder, pinion shafts, pressure rings and inner and outer clutch plates, and measure the total width. This measurement will be considered as value "B."
d. Select shims and adjust so that difference between differential case depth "A" and the sum of values "L," "B" and shim thickness "C" becomes the standard value.

Fig. 10 Clutch assembly. Limited slip differential:

6. On limited slip type units, apply clean gear oil to internal components, then assemble in reverse order of disassembly. Assemble clutch as shown.
7. Thoroughly clean drive gear attaching bolts and remove tape from threaded holes of drive gear using an M10 1.25 tap. Clean the holes with compressed air.
8. Apply Loctite No. 270, or 271, to drive gear threaded holes, then install gear onto case with reference marks aligned. Torque attaching bolts alternately, in a diagonal sequence, to 58-65 ft. lbs.
9. Press side bearings into differential case using tool MB990802.
10. Adjust drive gear backlash as follows:
a. Install side bearing adjusting spacers, thinner than those removed, to the side gear bearings, then install differential case assembly into gear carrier. Select adjusting spacers of the same thickness for both the drive pinion side and the drive gear side.
b. Push differential case to one side and measure clearance between gear carrier and side bearing adjusting spacer using two feeler gauges.
c. Remove side bearing adjusting spacers from one side and measure the thickness of adjusting spacers.
d. To determine proper thickness spacer to be used, add 0.002 inch to thickness measured in step c and one-half the clearance measured in step b.
e. Install one pair of the correct spacers each to the drive pinion side and drive gear side.
f. Install differential case assembly, with side bearing adjusting spacers, into gear carrier. Gently tap spacers with a brass drift to seat them on bearing outer race.
g. Install bearing cap with reference marks aligned. Torque cap bolts to 40-47 ft. lbs.

Fig. 11 Measuring drive gear backlash. Conquest:

Fig. 12 Adjusting drive gear backlash. Conquest:

h. With drive pinion locked in place, measure drive gear backlash, at four different points on the drive gear. If not within specifications, replace spacers as necessary to bring within specifications.

Fig. 13 Gear tooth contact pattern check:

i. Check drive gear and drive pinion for proper tooth contact by applying suitable marking compound to both surfaces of drive gear teeth. Insert a brass rod between carrier and case and rotate spline coupling by hand one revolution in each direction, while applying a load of approximately 2 ft. lbs. to the drive pinion. Adjust pinion height and backlash as needed until tooth contact pattern resembles standard pattern.

Fig. 14 Measuring drive gear backlash. Conquest:

11. Measure drive gear runout using a suitable dial indicator. If run out exceeds 0.002 inch, change position of drive gear in differential case and recheck.