9.75 Inch Axle

Backlash Adjustment (9.75 Inch Axle)

Tools Required
^ J25025 Guide Pins
^ J8001 Dial Indicator

1. Determine the differential side bearing preload and initial backlash.





2. Install the J25025 (1) and the J8001 (2, 3) to the axle housing as shown.
3. Place the indicator stem of the J8001 at the heel end of a gear tooth.
4. Set the J8001 so that the stem is aligned with the gear rotation and perpendicular to the tooth angle.
5. While holding the pinion stationary, move the ring gear back and forth.
Measure and record the backlash.
6. Repeat the measuring procedure at eight points around the ring gear.
Specification
The difference between the backlash at all of the measuring points should not vary by more than 0.05 mm (0.002 inch).
7. If the difference between the backlash at all of the measuring points varies by more than 0.05 mm (0.002 inch), inspect for the following conditions:
^ Burrs
^ A distorted case flange
^ Uneven bolting

8. If the difference between all the measuring points is within specifications, the backlash at the minimum lash point measured should be:
Specification
The backlash between the ring gear and the drive pinion should be between 0.08 - 0.25 mm (0.003 - 0.010 inch) with a preferred backlash of 0.13 - 0.20 mm (0.005 - 0.008 inch).

Important: Adjust the thickness of the shim pack on each side of the differential in equal amounts. This will maintain the correct axle side bearing preload.

9. If the backlash is not within specifications, adjust the backlash by doing the following:
9.1. Remove the differential side bearings.
9.2. If the backlash is too small, increase the backlash as follows:

Important: Moving 0.05 mm (0.002 inch) of shim thickness from one side of the differential to the other will change the backlash adjustment by 0.03 mm (0.001 inch).

9.2.1. Remove the appropriate amount of thickness from the left side shim pack. For example, to increase the backlash by 0.10 mm (0.004 inch), subtract 0.20 mm (0.008 inch) of thickness from the left side shim pack.
9.2.2. Add the 0.20 mm (0.008 inch) of shim thickness to the right side shim pack.

9.3. If the backlash is too large, decrease the backlash using the following procedure:

Important: Moving 0.05 mm (0.002 inch) of shim thickness from one side of the differential to the other will change the backlash adjustment by 0.03 mm (0.001 inch).

9.3.1. Remove the appropriate amount of thickness from the right side shim pack. For example, to decrease the backlash by 0.10 mm (0.004 inch), subtract 0.20 mm (0.008 inch) of thickness from the right side shim pack.
9.3.2. Add the 0.20 mm (0.008 inch) of shim thickness to the left side shim pack.
10. Install the left and right shim packs onto the differential case.
11. Install the differential side bearings.
13. Once backlash is correct, perform a gear tooth contact pattern check in order to ensure proper alignment between the ring and pinion gears.