Drive Pinion Shim Selection

Drive Pinion Shim Selection

Tools Required
^ J421681 Differential Centerline Cylinder
^ J421682 Shim Gage Assembly
^ J421689 Holding Strap
^ J4216811 Pinion Housing Centering Spacer
^ J42173 Differential Holding Fixture

Important: The pinion depth adjustment procedure and shim selection must be performed prior to pinion shaft and housing assembly.





1. Install the differential assembly (1) onto the J42173 (2).

Notice: Refer to Fastener Notice in Service Precautions.

2. Install 4 M8 x 1.25 bolts (3).
Tighten the bolts to 25 Nm (18 ft. lbs.).





3. Install the J421681 into the left bearing race bore of the differential housing.





4. Install the J421689 and thumbscrew to the J421681. Tighten the thumbscrew until snug.





5. Install the bearing races into the pinion housing/cage (4).
6. Install the J4216811 (2), bearings (3 and 6), spacer (5), J421682 (7), and bolt (1) to the pinion housing/cage (4). Tighten the bolt until sung.





7. Install the pinion housing/cage assembly (1) into the differential housing.
The use of M8 x 1.25 dowels or long bolts will ease in pinion housing installation and alignment.





Important: ALL of the pinion housing/cage bolts must be installed in order to obtain an accurate measurement and correct shim selection.

8. Install the pinion housing/cage bolts (1).
Tighten the bolts to 25 Nm (18 ft. lbs.).





9. Using a feeler gage, measure the distance between the J421682and the J421681. Record the dimension as B1.
10. Subtract the B1 value from a B nominal value of 5 mm (0.197 inch). Record that calculation as B2.
Refer to the applicable calculation tables in Spacer and Shim Specifications.





11. Locate the A1 value (1) on the side of the ring gear.

Important: The A1 value is a manufacturing variation between the ring gear and pinion. The A1 value may be higher, lower, or equal to 103.00 mm (4.055 inch) nominal value. When subtracting the A nominal value from the A1 value, the B3 calculation may compute to a positive, negative, or zero total

12. Subtract the A nominal value of 103.00 mm (4.055 inch) from the A1 value. Record the calculation as B3.
13. Add the B2 value to the B3 value for the proper pinion housing shim thickness. The B3 value may be a positive, negative, or zero value.
14. Select shims equal to the calculated value. It may be necessary to round the shim or shims total to obtain the proper size shim pack. If the shim thickness calculation is past the midpoint value, round the number higher to the next decimal value.
Refer to Rear Axle Specifications.