Rear Axle Total Backlash

If vehicle vibrates and has a booming sound due to system driveline imbalance. Total axle backlash should be checked. To check backlash, proceed as follows:
1. Place gearshift in neutral, apply parking brake, then raise and support vehicle.

Fig.23 Rear Axle Total Backlash Check:

2. Manually turn propeller shaft clockwise as far as it will go and scribe mating mark on companion flange dust cover and differential carrier.
3. Manually turn shaft counterclockwise as far as it will go and measure movement of mating marks.
4. If axle total backlash is less than .2 inch (5 mm), backlash is satisfactory.
5. If backlash is more than 0.2 inch (5 mm), adjust as necessary.