9.75 Inch, 10.5 Inch Axles

Backlash Adjustment (9.75 Inch, 10.5 Inch Axles)

Tools Required
^ J8001 Dial Indicator Set
^ J24429 Side Bearing Backlash Spanner
^ J25025 Guide Pins





1. Install the J25025-1 and the J8001 to the axle housing as shown.
2. Place the indicator stem of the J8001-3 at the heel end of a gear tooth.
3. Set the J8001-3 so that the stem is aligned with the gear rotation and perpendicular to the tooth angle.
4. Preload the dial of the J8001-3.
Align the needle and the dial face of the J8001-3 to ZERO.
5. While holding the drive 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.
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:
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 - 0.18 mm (0.005 - 0.007 inch).
9. If the backlash is too small, increase the backlash by turning the left differential bearing adjuster in one slot and the right differential bearing adjuster out one slot using the J24429 until the correct backlash is obtained.
10. If the backlash is too large, decrease the backlash by turning the right differential bearing adjuster in one slot and the left differential bearing adjuster out one slot using the J24429 until the correct backlash is obtained.
11. Recheck the backlash following the steps above to verify that the backlash is within specifications.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

12. Tighten the differential bearing caps and bolts.

Tighten the bolts to 109 Nm (80 ft. lbs.).
13. Recheck the backlash and adjust, if necessary.
14. Once backlash is correct, perform a gear tooth contact pattern check in order to ensure proper alignment between the ring and pinion gears.