Differential Assembly: Adjustments

Side Gear Backlash

Fig. 5 Measuring Side Gear Backlash:

Fig. 6 Side Gear Thrust Washer Chart:

1. Assemble differential gearing and case as shown in Fig. 5. Torque case half bolts to 27-32.5 ft. lbs.
2. Using a suitable vernier caliper and a piece of solder as shown in Fig. 5, measure side gear backlash. Backlash should be 0.002-0.006 inch (0.05-0.15mm).
3. Using a suitable dial indicator, measure side gear thrust play. Thrust play should be 0.005-0.014 inch (0.12-0.37mm).
4. If measurements are not within specifications, increase or decrease thickness of thrust washers on inner side of each case half with appropriate thrust washer as shown, Fig. 6.

Bevel Pinion Shim Thickness

Thickness of shims to be used on bevel pinion varies from one vehicle to another due to machining during assembly. Therefore, for each vehicle, the thickness of shims necessary for locating pinion in correct (producing proper backlash between pinion and gear) must be determined when reassembling.

Fig. 7 Installing Dial Indicator On Dummy Pinion:

Fig. 8 Installing Dummy Pinion On Surface Plate:

Fig. 9 Measuring Pinion Starting Torque:

Fig. 10 Determining Shim Thickness:

Fig. 11 Bevel Pinion Shim Thickness Chart:

To facilitate this determination, a two piece dummy tool is available. The following procedure is based on the use with the dummy tool set in the carrier, without any shims as follows:
1. Install a suitable dial indicator on dummy pinion, allowing indicator spindle to protrude 5-6mm from bottom of pinion dummy as shown in Fig. 7.
2. Rest dummy on surface plate, then set dial indicator to zero, Fig. 8.
3. Install dummy pinion with bearings into carrier, then the joint flange.
4. Tighten bevel pinion by hand, then install differential gear preload adjuster 09922-75221, Fig. 9, on universal joint flange.
5. Using a suitable spring scale, turn pinion several times, tighten pinion nut gradually until pinion starting torque reaches 4.0-7.5 lbs., Fig. 9.
6. Referring to Fig. 10, note that there are three dimensions, a, b and c. The value of ``b'' is unknown at this time. The values of ``a'' and ``c'' are given. The sum ``a'' + ``c,'' is 94mm, which is indicated on the dummy tool.
7. With dummy tool installed, the dial indicator pointer may have deflected from ``0'' mark to a certain value, note value, that value is now ``b.'' Add this value to 94mm and from the total, subtract value marked on bevel pinion. The remainder is the required shim thickness.
8. There are 12 selective shim thicknesses. Select one or two shim(s) from chart, Fig. 11, to obtain the closest thickness to required thickness, then install shim piece(s) into clearance (1) as shown in Fig. 10.

Pinion Bearing Preload

The bevel pinion, installed in the carrier, is required to offer a certain torque resistance when checked by using preload adjuster 09922-75221 (A), Fig. 9. This resistance is a ``preload'' which is due to the tightness of the two tapered bearings by which the pinion is held in carrier. This tightness is determined primarily by tightening torque of bevel pinion nut. Pinion bearing preload should be 7.8-14.7 inch lbs. Adjust preload of bevel pinion bearings, if necessary, as follows:
1. Install pinion bearings, spacer, bevel pinion, oil seal and universal joint flange to differential carrier. Apply gear oil to bearings and grease oil seal lip.
2. Tighten bevel pinion nut by hand, then install preload adjuster 09922-75221 to universal joint flange.
3. Turn pinion several times, then tighten pinion nut gradually while checking pinion starting torque, using a suitable spring scale, Fig. 9. Starting torque should be 4.0-7.5 lbs.
4. Stake bevel pinion nut to prevent it from loosening. Pinion bearing preload is adjusted by tightening bevel pinion nut to compress spacer. Ensure to use a new spacer for adjustment. If specification exceeds limit, replace spacer and repeat preload adjustment procedure.

Bevel Gear Backlash

Fig. 12 Measuring Backlash Between Bevel Gear & Pinion:

Fig. 13 Drive Bevel Pinion Graphic Chart:

Backlash between bevel gear and pinion is checked using a suitable dial indicator as shown in Fig. 12. The differential case assembly is mounted in the normal manner, and fastened down by tightening side bearing cap bolts to 7.7-14 ft. lbs. Screw in each adjuster until it contacts bearing outer race so that outer race is prevented from inclining. The dial indicator spindle is pointed squarely to ``heel'' on drive side (convex side) of gear tooth. Hold bevel pinion, then turn gear back and forth. Bevel gear backlash should be 0.004-0.006 inch (0.10-0.15mm).
To increase or decrease backlash, displace bevel gear toward or away from pinion by turning in one adjuster and turning out the other by equal amounts. Turning adjuster one notch changes backlash approximately 0.002 inch (0.05mm). Adjust preload on side bearing during backlash adjustment using a suitable spring scale and mounting preload adjuster 09922-75221 as shown in Fig. 9. If reading at bevel gear starts moving within range given in Fig. 13, side bearing preload is acceptable. Referring to Fig. 13, for example, when drive bevel pinion bearing preload measures 5.73 lbs., drive bevel pinion bearing preload + bevel gear side bearing preload should be 6.17-7.05 lbs. After adjustment, torque bearing cap bolts to 51-72 ft. lbs.