Assembly

Fig. 13 Side gear & thrust washer installation:

I-MARK & IMPULSE

1. Install the side gears and thrust washers in the differential case, Fig. 13.
2. Lubricate and install pinion gears 180 degrees apart and rotate the gears as an assembly until the pinion gear bores are aligned with the pinion shaft bores in the case.

Fig. 14 Pinion shaft installation:

3. Install pinion shaft, Fig. 14.

Fig. 15 Measuring backlash between side gears & pinion gears:

4. Using a dial indicator measure the amount of backlash between the side gears and the pinion gears, Fig. 15. One side gear must be held stationary while making this test. If backlash is greater than .003 inch, make necessary adjustments with the thrust washers, available in thickness of .037 to .055 inch. Increasing washer thickness will decrease backlash while decreasing washer thickness will increase backlash.
5. Install lock pin into pinion shaft and caulk its end to prevent loosening.
6. Install ring gear on case making sure their mating surfaces are free of burrs or foreign material. Tighten bolt to 47 ft. lbs.
7. Check lateral runout of installed ring gear. Maximum permissible runout is .003 inch. If runout is greater than specified, make certain that dirt or burrs are not holding the ring gear in a cocked position on the case and that the bolts are evenly torqued.

Fig. 16 Differential side bearing installation:

8. Install side bearings using installer J-22919 and drive handle J-8092, Fig. 16. Support opposite side of case on pilot J-2241-11 to prevent bearing damage.
9. Determine differential side bearing preload and backlash as follows:
a. Position differential case assembly less side bearing shims into the side bearing shims into the side bearing bores of the carrier.

Fig. 17 Check bearing preload & endplay:

b. Using two sets of feeler gauges, insert feeler stock of sufficient thickness between each bearing outer race and the carrier to remove all endplay, Fig. 17. Make certain the feeler stock is pushed to the bottom of the bearing bores.
c. Mount dial indicator J-8001 on carrier so indicator stem is at right angles to a tooth on the ring gear.
d. Adjust feeler gauge thickness from side to side until ring gear backlash is .005 to .007 inch (.006 inch is desired).
e. With zero endplay and correct backlash established, remove feeler gauge packs, determine thickness of shims required and add .002'' to each shim pack to provide side bearing preload.
f. Remove case assembly and both side bearings using J-22588 with adapter leg J-22939 and pilot J-2241-11.
g. Install shim packs with respective side bearing using installer J-22919, driver handle J-8092 and pilot J-2241-11.
10. Position case assembly and outer races in the carrier. Use a soft faced hammer to drive the case into the carrier until the side bearing outer races bottom in their bores.
11. Install the side bearing caps in their original location and torque bolts to 35 ft. lbs.
12. Rotate case assembly several times to seat the bearings. Check backlash and preload using a torque wrench on a ring gear attaching bolt. Torque required to turn case should be 20 to 30 inch lbs. for new bearings or 10 to 20 inch lbs. for used bearings. If torque is not correct, it will be necessary to re-shim the side bearings.
13. Install torque tube assembly.
14. Install axle shafts.

PICKUP & TROOPER II

Setting Pinion Depth
1. Install drive pinion front and rear outer races. On rear differentials use tool J-8092 with adapter J-24256 for front race and J-24252 for rear race. On front differential use tool J-29039 for front race and J-29038 for rear race.
2. Lubricate and install front and rear bearings to be used for final assembly into their respective races.
3. On rear differentials install gauging plate J-23597-7 and preload stud and pilot J-23597-9 through front and rear bearings and tighten nut. On front differentials install gauging plate J-23597-26 and preload stud and pilot J-23597-27 through rear bearing and J-23597-21 through front bearing and tighten nut.
4. Rotate bearings to assure proper seating, then tighten locknut until 20 inch lbs. (2.2 Nm) of torque are required to rotate new bearings, or 8-10 inch lbs. (1.0-1.2 Nm) of torque are required to rotate used bearings.
5. Place discs J-23597-8 for rear differentials or J-23597-6 for front differentials onto arbor J-23497-1, then place tool into side bearing bores and install bearing caps snugly.

Fig. 18 Checking pinion depth:

6. Install dial indicator on arbor post, then preload dial indicator one half turn and tighten indicator in this position, Fig. 18.
7. Position dial indicator plunger on gauge plate and slowly move it across gauge plate until highest reading is obtained. Zero dial indicator on highest reading of gauge plate, Fig. 18.

Fig. 19 Pinion depth code:

8. Carefully swing plunger off gauge plate and note reading on dial indicator. Recheck to verify reading. The reading on the dial is the correct dimension for the rear pinion depth shim on a ``nominal'' pinion. Check drive pinion head markings. The pinion depth code which is in the lowest position of the three numbers, Fig. 19, indicates a necessary change in pinion mounting distance. A plus number indicates the need for a greater mounting distance (achieved by decreasing shim thickness). A minus number indicates the need for a smaller mounting distance (achieved by increasing shim thickness). If no pinion depth code is stamped on the head, the pinion is ``nominal.'' In this case, proceed to step 10.

Fig. 20 Pinion depth chart:

Fig. 21 Pinion depth chart:

9. Using chart in Fig. 20 or 21, determine proper shim variation to compensate for plus or minus markings. Shims are available in sizes ranging from .086-101 inch (2.18-2.56 mm) for rear differentials or .059-.077 inch for front differentials. An indicator reading of .001 inch (.000 or .003 mm) requires shims of .100 and .101 inch (2.54 and 2.57 mm) respectively.
10. Place shim on drive pinion, then install rear bearing using tool J-6133 and an arbor press. Do not press on roller cage. Press on inner race only.

Pinion Bearing Preload
1. Place drive pinion and collapsible spacer into carrier.
2. Lubricate and position front bearing to be used during final assembly into carrier, then install new oil seals.
3. Install companion flange on drive pinion, then apply hypoid lubricant to threads and install new pinion nut. On rear differentials torque nut to 85 ft. lbs. On front differentials torque nut to 125 ft. lbs.
4. Rotate drive pinion to insure that bearings are fully seated, then wind about 4-6 turns of string around pinion flange. Using a pull scale, check amount of pull required to rotate flange.
5. Continue to tighten pinion nut in small increments until pull required to rotate flange is 17 lbs. (7.7 kg) for new bearings, or 7-9 lbs. (3.2-4.1 kg) for used bearings. The pinion nut should be tightened only in small increments and the pull scale used after each tightening. Exceeding preload specifications will compress spacer too much and require its replacement.

Differential Case Reassembly
1. Install side gears and thrust washers in differential case.

Fig. 22 Positioning pinion gears:

2. Position pinion gears 180° apart, Fig. 22, then roll gears into position, making sure they are aligned, to allow installation of pinion shaft.
3. Place thrust block between pinion gears and drive pinion into place. Make sure that lock pin hole in cross shaft lock aligns with hole in case.
4. Check backlash between differential gears and pinion gears. If backlash is greater than .003 inch (.08 mm), make necessary adjustments with thrust washers. Thrust washers are available in thicknesses of .041, .045, .049 and .053 inch (1.04, 1.14, 1.24 and 1.35 mm). Increasing washer thickness will decrease backlash. Decreasing washer thickness will increase backlash.

Fig. 23 Installing lock pin.:

5. Install cross shaft lock pin, Fig. 23, and caulk its end to avoid loosening.

Fig. 24 Ring gear bolts torquing sequence. Rear differentials:

Fig. 25 Ring gear bolts torquing sequence. Front differentials:

6. Clean ring gear bolts and apply Loctite to threaded portion of bolts. Install ring gear, then install and torque bolts to 80-87 ft. lbs. for rear differentials or 44-58 ft. lbs. for front differentials in sequence shown in Figs. 24 and 25.

Side Bearing Preload & Initial Backlash Setting
If original side bearings, differential case, ring gear and pinion and differential carrier are being used, and if pattern check taken prior to disassembly showed proper tooth contact, the original (or new shims of the same thickness) may be reinstalled in their original locations. If new side bearings are being installed, and if pattern check taken prior to disassembly showed proper tooth contact, the following alternate procedure of shim selection may be used.
1. Using a micrometer, measure new bearing thickness and compare it with the old one.
2. If new bearing is thicker, subtract numerical difference between new and old bearing from shim pack.
3. If new bearing is thinner, add numerical difference between new and old bearing to original shim pack. If new bearings and/or differential case, ring and pinion or differential carrier are being installed, new shims will have to be selected for installation behind side bearings as follows.
4. Install side bearings to be used during final assembly on differential case. Do not install shims at this time. For rear differentials use tool J-24244 for first bearing, then support case on J-8107-2 and install opposite bearing. For front differentials use tools J-8092 and J-29036 for first bearing, then support case on tool J-8107-2 and install opposite bearing.

Fig. 26 Checking side bearing clearance:

5. Mount case into carrier bores, then move ring gear tight against ring gear side and away from pinion and hold in this position. Using a feeler gauge just thick enough to produce a slight drag, measure clearance between bearing and differential carrier on side opposite ring gear, Fig. 26. Record thickness.
6. Determine proper shims for installation. A predetermined dimension of .002 inch (.05 mm) is always required for proper preload. Therefore, add .002 inch (.05 mm) for proper preload to clearance measured in step 5. This will provide the necessary combined total thickness of both shim packs.
7. Divide total dimension into two shim packs so that numerical difference between packs equals numerical difference between the original shim packs.

Fig. 27 Installing bearing shims:

8. Remove case from carrier, then carefully remove both side bearings. Install shims as determined in steps 6 and 7 behind each bearing, Fig. 27, and install bearings into case.
9. Install case onto carrier, tapping carefully into place, then install bearing caps into original locations and torque bolts to 75 ft. lbs. for rear differentials or 50 ft. lbs. for front differentials.

Fig. 28 Checking ring gear runout:

10. Check ring gear runout, Fig. 28. If runout exceeds .002 inch (.5 mm), correct by cleaning or replacing parts as necessary.

Fig. 29 Checking backlash:

11. Install dial indicator against ring gear teeth making sure indicator button is perpendicular with tooth travel, Fig. 29. If backlash is not within .005-007 inch for rear differentials or .004-006 inch for front differentials, the shims behind each side bearing must be adjusted. In order to maintain proper preload when backlash is adjusted, the total thickness of both shim packs will have to be adjusted. Therefore, if necessary to increase one shim pack, the opposite shim pack will have to be deceased an equal amount.
12. To increase backlash, increase right side bearing shim and decrease left side bearing shim. To decrease backlash, decrease right side bearing shim and increase left side bearing shim. Backlash changes about .002 inch (.05 mm) for each .003 inch (.08 mm) shim change.

Gear Tooth Contact Pattern
Prior to final assembly, a ``Gear Tooth Contact Pattern'' check is necessary to assure correct relationship between gear sets. Gear sets which are ill positioned may be noisy and have a short life. With a contact pattern check, the most desirable contact between ring gear and drive pinion can be assured.
1. Wipe oil out of carrier and carefully clean each ring gear tooth.
2. Apply marking compound sparingly to all ring gear teeth using a medium stiff brush. When properly used, the pinion tooth contact area will be visible when a hand load is applied.
3. Apply a hand load to companion flange and rotate ring gear one revolution in each direction. Excessive turning of ring gear is not recommended.

Fig. 30 Gear tooth contact pattern:

4. Observe pattern made on ring gear teeth and compare with Fig. 30. A correct contact pattern should be centrally located up and down on the face of the ring gear teeth.

Contact Pattern Adjustment
Backlash and position of drive pinion in differential carrier are the only two adjustments which can be made that will affect the contact pattern. The effects of bearing preload adjustments are not readily apparent with tooth pattern checks. However, these adjustments should be within specifications before proceeding with backlash and drive pinion adjustments.
The drive pinion position is adjusted by increasing or decreasing the shim thickness between the pinion head and inner race of rear bearing. Increasing the shim thickness will move the pinion closer to center line of ring gear. Decreasing shim thickness will move pinion farther away from center line of ring pinion.
The backlash is adjusted by means of the side bearing adjusting shims which moves the entire case and ring gear assembly closer to or further away from the drive pinion. To increase backlash, increase right shim and decrease left shim an equal amount. To decrease backlash, decrease right shim and increase left shim an equal amount.
It may be necessary to adjust both pinon depth and backlash to obtain the correct pattern.