Pinion Depth Adjustment

- Tools Required:
- J 8001 Dial Indicator Gage Set
- J 21777-1 Arbor
- J 21777-29 Gage Plate
- J 21777-35 Rear Pilot Washer
- J 21777-42 Front Pilot Washer
- J 21777-43 Stud Assembly-Bolt
- J 21777-45 Side Bearing Disc

1. Clean all the gage parts.
2. Lubricate the front and rear pinion bearings with axle lubricant.
3. Place the bearings into the pinion bearing cups.





4. Install J 21777-35, J 21777-42, J 21777-29, and J 21777-43 to the pinion bore.
5. Hold the stud stationary at the flats of the stud.
- Tighten stud nut to 2.2 Nm (20 inch lbs.).
6. Rotate the gage plate and bearings several complete revolutions to seat the bearings.
7. Tighten the stud nut until a torque of 1.6 to 2.2 Nm (15 to 25 inch lbs.) is obtained to keep the gage plate in rotation.





8. Assemble J 21777-45, J 21777-1, and J 8001 to the differential bearing bore as shown.
- The bearing bores must be clean and burr free.
9. Install the side bearing caps.
- Tighten bolts finger tight.
10. Rotate the gage plate until the proper gaging area is parallel with the discs.
11. Position the gage shaft assembly in the carrier so the dial indicator rod is centered on the gage area of the gage block.
12. Set the dial indicator at zero. Push the indicator down on the indicator shaft until the needle rotates approximately 3/4 of a turn to the right. Tighten the dial indicator in this position.
13. Rotate the gage shaft slowly back and forth until the dial indicator reads the greatest deflection. This is when the indicator needle is centered between movement to the left and to the right.
14. At the point of greatest deflection, set the dial indicator to zero. Repeat the rocking action of the gage shaft to verify the zero setting.





15. Rotate the gage shaft until the dial indicator rod does not touch the gage block. Record the actual number on the dial indicator and not the number which represents how far the needle travels. This is the nominal pinion setting. EXAMPLE: The indicator needle moved counter clockwise 1.70 mm (0.067 inch) to a dial reading of 0.84 mm (0.033 inch). Record the dial reading of 0.84 mm (0.033 inch), NOT 1.70 mm (0.067 inch).
16. Check the pinion face for a pinion adjustment mark. This mark indicates the best running position for the pinion from the nominal setting.
- If the pinion has no plus or minus marked on it, use the nominal pinion setting to select a shim.
17. Remove bearing caps (10) and depth gaging tools.
18. Install the correct pinion shim (6) to the pinion according to this procedure.

NOTICE: Proper pinion depth setting Is a two-step procedure.
1. Setup dimension arrived at with the Indicator to be considered a starting polar.
2. Gear tooth pattern check is necessary to "fine tune" the pinion depth and may indicate additional shim changes to the pinion stem. Both procedures must be performed to ensure proper axle performance and prevent system damage.