Inspection Before Disassembly

Inspection Before Disassembly of Axle

Axle Backlash Check

Clunk is due to backlash in the driveline, but not necessarily in the rear axle. To determine whether driveline clunk is caused by the rear axle, make a check of the total axle backlash as follows.

1. NOTE: Do not perform this procedure for limited slip axles. There is no effective way to check backlash on limited slip axles.

Raise the vehicle on a frame or twin-post hoist so that the rear wheels are free.

2. Clamp a bar between the rear axle companion flange and a part of the frame or body so that the rear axle companion flange cannot move.






3. Lock the left rear wheel to keep it from turning.






4. Turn the right wheel slowly until you "feel" it in a drive condition. Hold a chalk marker on the side of the tire 304.8mm (12 inches) from the center of the wheel.
5. Turn the wheel the other way until you again feel the drive condition.

6. Measure the length of the chalk mark, which is the total axle backlash. It should be 25.4mm (1 inch) or less.

If the backlash is within this limit, the clunk will not be eliminated by going into the axle.

7. Check for these conditions if the backlash is excessive:
- Elongation of the differential pinion shaft holes in the differential case.
- Missing differential pinion thrust washer or differential side gear thrust washer.
- Galling of the differential pinion shaft and bore.

If none of the above conditions show up, there may be a loose fit of the axle shafts to the side gear splines. You should continue as follows until the correction is made.
- Install new differential side gear and recheck the backlash.
- Install two new axle shafts.

Ring and Pinion Backlash Check

SPECIAL SERVICE TOOL(S) REQUIRED
Description Pinion Depth Gauge
Tool Number T79P-4020-A

The differential case and drive pinion should be inspected before they are removed from the differential carrier casting. These inspections can help find the cause of the concern and determine the correction needed.

1. Wipe the lubricant from the internal working parts and visually inspect the parts for wear or damage.
2. Rotate the gears to see if there is any roughness which would indicate worn or damaged bearings or gears.
3. Check the ring gear and pinion teeth for signs of scoring, abnormal wear or nicks/chips.

4. NOTE: On vehicles equipped with rear anti-lock brakes (RABS), mount Dial Indicator with Bracketry TOOL-4201-C or equivalent on the carrier so the tip of the dial indicator contacts the backface of the ring gear and pinion. There is a space provided between the anti-lock speed sensor ring and the ring gear and pinion for measuring ring gear and pinion backface runout.

Set up a dial indicator, and check ring gear and pinion backlash and ring gear and pinion backface runout.

5. NOTE: Mount Dial Indicator with Bracketry TOOL-4201-C or equivalent on the carrier so the tip of the dial indicator contacts the backface of the ring gear (part of ring gear and pinion). There is a space provided between the anti-lock speed sensor ring and the ring gear from measuring ring gear backface runout.






Position dial indicator as shown and check ring gear backface runout.