Differential Assembly: Service and Repair

Fig. 1 Differential exploded view:

4WD WAGON

DISASSEMBLY

1. Loosen peened area of locknut, Fig. 1.
2. Using Companion Flange Holder 07926-SD90000 or equivalent, remove locknut and flange.
3. Apply identification punch marks on side bearing caps for reassembly purpose.
4. Remove bearing caps attaching bolts, then bearing caps and differential case from carrier.
5. Using a plastic hammer, remove drive pinion from carrier.
6. Remove drive pinion oil seal and front drive pinion bearing from carrier.
7. Using a suitable screwdriver, remove front pinion bearing race and rear pinion bearing race from carrier.
8. Using a suitable puller, remove rear drive pinion bearing from drive pinion.
9. Using a suitable puller, remove both differential side bearings.
10. Remove ring gear attaching bolts, then ring gear from differential case. Ring gear bolts have right handed threads.
11. Using a hammer, drive spring pin out of pinion shaft.
12. Remove pinion shaft from differential case, then differential side gears and pinions.

Fig. 2 Installing pinion center pins:

Fig. 3 Thrust washer chart:

ASSEMBLY

1. Install differential side gears into case by installing Differential Pinion Center Pin 07973-SD90300 or equivalent through case into side gears, Fig. 2.
2. Install differential pinions and thrust washers, then pinion shaft.
3. Place differential case assembly in V-blocks.
4. Using a suitable dial gauge, measure backlash between side gears and pinion gears. Backlash should be .0020-.0060 inch. If backlash does not meet specifications, select new pinion thrust washers from chart, Fig. 3, until specifications are met.
5. Using a suitable drift, install spring pin through differential case into pinion shaft.
6. Install ring gear on differential case and torque bolts to 74 ft. lbs.
7. Using a suitable press, install side bearings inner race onto differential housing.
8. Using Driver 07749-0010000 and Attachment 07746-0010600 or equivalent, install rear pinion bearing race.
9. Using Driver 07749-0010000 and Attachment 07947-SD90100 or equivalent, install front pinion bearing race.

Fig. 4 Installing pinion bearings:

10. Install pinion bearings on Dummy Pinion Shaft 07973-SD90100 on 1985 models, or 07973-SD9090A on except 1985 models or equivalent, then install assembly into carrier, Fig. 4.
11. Install companion flange, lock washer and locknut on dummy pinion shaft.
12. Use a suitable screwdriver to prevent dummy shaft from turning, then torque locknut to 7 ft. lbs.
13. Check pinion preload. Preload should be 7.8-10.4 inch lbs. If not within specifications, turn locknut until correct preload is obtained.
14. Using a suitable pinion height block, set dial indicator needle at 0. Install pinion height block into carrier with dial indicator resting on dummy shaft. Install bearing caps and torque bolts to 40 ft. lbs.
15. Rotate height block to measure pinion height. The lowest reading on indicator is appropriate measurement.
16. Calculate shim thickness needed as follows:
a. If number etched on pinion is a (-) number, add number to value obtained in step 15. The plus or minus number on pinion represents matching tolerance in hundredths of a millimeter.

Fig. 5 Pinion shim selection chart:

b. Example; Value obtained in step 15 is 0.85 mm, mark on pinion is plus 2, 0.85 mm - 0.02 mm = 0.83 mm shim thickness. Refer to Fig. 5 for pinion shim selection chart.
17. Using Driver 07946-MB00000 or equivalent, install rear pinion bearing and shim selected onto drive pinion.
18. Install drive pinion assembly into carrier.
19. Install front pinion bearing, companion flange, lock washer and locknut. Install lock washer with dished side inward.
20. Using Companion Flange Holder 07926-SD90000 or equivalent, hold companion flange and torque locknut to 7.23 ft. lbs.
21. Check pinion bearing preload. Preload should be 7.8-10.4 inch lbs. If not, turn locknut until correct preload is obtained.
22. Install differential case into carrier, and push case to move ring away from drive pinion. Measure clearance between side bearing and carrier using a suitable feeler gauge.

Fig. 6 Side bearing selection chart:

23. Determine shim thickness by adding 0.03 to 0.06 mm to clearance measured in step 22, then divide by 2. Example: clearance measured is 5.52 mm + 0.06 mm = 5.57 mm divided by 2 = 2.79 mm. Refer to side bearing shim selection chart, Fig. 6.
24. Install shims selected between side bearing and carrier.
25. Install bearing caps and torque bolts to 40 ft. lbs. Align marks made previously during disassembly.
26. Using a suitable dial gauge, measure backlash between ring gear and drive pinion. Backlash should be .0043-.0063 inch. If not, correct by decreasing shim thickness on one side and increasing thickness of other shim the same amount.
27. When correct backlash is obtained, check total bearing preload.
28. Check teeth contact between ring gear and drive pinion.
29. Remove differential case from carrier.
30. Remove locknut, lock washer, companion flange, drive pinion and front drive pinion bearing.
31. Install drive pinion in carrier using a new pinion spacer.
32. Install front drive pinion bearing and drive pinion oil seal.
33. Install companion flange, lock washer and locknut.
34. Using Companion Flange Holder 07926-SD90000 or equivalent, torque locknut to 86-166 ft. lbs.
35. Check preload. Preload should be 10-13 inch lbs.
36. Peen locknut and install differential case in carrier.
37. Check gear tooth contact and total preload. Drive pinion preload 10-13 inch lbs. plus differential case preload 3.4-5.2 inch lbs.