What is Backlash?
Which also can be referred to as a lash or play, (according to the definition of wikipedia) is "the maximum distance or angle through which any part of a mechanical system may be moved in one direction without applying appreciable force or motion to the next part in mechanical sequence".
What is differential? It is a gear train in an automobile which is capable of determining the differences in speed and direction of motion.
Now that we have tried defined backlash and differential, let's consider the definition of Rear Axle. Rear axle is the pin or spindle positioned at the rear of an automobile or car on which a wheel revolves, or which revolves with a wheel.
How to check and correct backlash on the rear axle.
(1) Remount the dial indicator on the gear carrier housing with the button against one of the drive gear teeth, as nearly in line with the direction of tooth travel as possible.
(2) Move the drive gear by hand to check the backlash which should be etched on the gear.
(3) If the backlash is not in accordance with the specification transfer the necessary shims from one side of the differential case to the other to obtain the desired setting.
(4) To increase backlash, remove shims from the drive gear side of the differential and install on opposite side.
(5) Backlash is decreased by transferring shims to the drive gear side from the opposite side of the differential case.
Hopefully, the above points should be of great help.