Total Backlash Check
Total Backlash Check1. Raise and support the vehicle.
2. Remove the driveshaft.
3. Install the special tool.
- Clamp a rigid bar or pipe to the tool. Clamp the other end of the bar or pipe to the frame or a body member in order to prevent movement of the pinion flange.
4. Lower the vehicle so that one rear wheel is resting on a wheel chock to prevent it from turning. The other rear wheel will be used to measure total rear axle backlash.
5. Rotate the free wheel slowly, by hand, until the feeling of driving the rear axle is encountered. Place a mark on the side of the tire, 305 mm (12 inches) from the center of the wheel, with a crayon or chalk.
6. While holding the crayon or chalk against the tire, rotate the wheel slowly in the opposite direction until the feeling of driving the rear axle is encountered again.
7. Measure the length of the crayon or chalk mark on the tire.
- If the length of the mark is 25.4 mm (1 inch) or less, the rear axle backlash is within allowable limits.
- If the chalk mark is greater than 25.4 mm (1 inch), check for these conditions:
- Elongation of the differential pinion shaft and holes in the differential case.
- Missing differential pinion thrust washer or differential side gear thrust washer.
- Galling of the differential pinion shaft and bore.
- Excessive ring gear and pinion backlash. Follow the procedure for the type of rear axle to check backlash.