Differential Service

Fig. 3 Ring gear removal:

DISASSEMBLY

1. If original matching marks are not clear, scribe matching marks between differential case halves to aid assembly.
2. Remove differential case bolts, noting position for assembly, then separate case halves.
3. Remove differential pinion spider, along with pinions and thrust washers, keeping components in order.
4. Remove side gear and thrust washer from each case half.
5. Remove case side bearings, as needed, using suitable puller.
6. If ring gear is to be replaced, proceed as follows:
a. Carefully center punch center of each rivet head.
b. Using drill 1/32 inch smaller than body of rivet, drill completely through each rivet securing ring gear, Fig. 3.
c. Press out rivets and remove ring gear.
7. Inspect components as outlined and replace as needed.

Fig. 1 Timken/Rockwell drive axle w/12 inch ring gear exploded view:

Fig. 4 Differential case assembly:

Fig. 5 Differential rolling resistance check:

ASSEMBLY

1. Install ring gear as follows:
a. Immerse ring gear in water heated to 160-180°F. for approximately 10 minutes.
b. Align gear over case pilot and install ring gear on differential case. Gear should not be driven or pressed onto case as metal particles may become lodged between gear and case causing excessive runout.
c. Install new ring gear retaining bolts from service package and torque bolts to 85-115 ft. lbs.
2. Install side gear and thrust washer in ring gear half of case, Fig. 1. Coat all components with specified axle lubricant during assembly. Components that are reused must be installed in original position.
3. Mount differential pinions and thrust washers on spider and install assembly in ring half of case, ensuring that spider is fully seated.
4. Position side gear and thrust washer on pinion assembly, align matching marks, then install remaining case half, Fig. 4.
5. Install 4 case retaining bolts, evenly spaced, and draw case halves together by tightening bolts evenly and alternately.
6. Install remaining case bolts and torque all bolts to 60-75 ft. lbs.
7. Press side bearings onto case using suitable spacer and pilot.
8. Check rolling resistance of side gear and pinion assemblies as follows:
a. Fabricate checking tool by cutting splines from axle shaft and welding nut onto unsplined end, Fig. 5.
b. Mount case assembly inside taking care not to damage components.
c. Insert stub axle into side gear and rotate assembly with suitable torque wrench.
d. If rolling resistance exceeds 50 ft. lbs. when rotating one side gear, recheck differential assembly and correct as needed.