Drive Pinion and Gearset

Tools Required:

• Pinion Depth Gauge Set T79P-4020-A

A selective pinion shim (0.254mm to 0.965mm (0.010 to 0.038 inch)) is used between pinion rear bearing and pinion head. The shim compensates for machining variations in carrier, pinion and pinion bearings. The correct shim size will locate pinion for proper tooth contact with ring gear. Selecting correct pinion shim when installing a new gearset can be done by using Pinion Depth Gauge Set T79P-4020-A as outlined.

Pinion Depth Gauge Procedure

1. Refer to illustration and assemble the appropriate aligning adapter, gauge disc and gauge block to the screw.

NOTE: The gauge block must be offset to obtain an accurate reading.

2. Place rear pinion bearing (new, or used if in good condition) over aligning disc and insert into pinion bearing cup of the carrier. Place front bearing into the bearing cap and assemble the tool handle into screw and tighten to 2.26 Nm (20 lb-in).
   
   
   
   

3. Make sure that the gauge handle adapter screw, aligning adapter, gauge disc and gauge block assembly are securely mounted between the front and rear bearing. Check the tool handle torque prior to gauging to ensure that bearings are properly seated. This can affect final shim selection when improperly assembled. Clean bearing cups and differential pedestal surfaces thoroughly. Apply only light oil film on bearing assemblies prior to gauging.

4. The gauge block should then be rotated several half turns to ensure rollers are properly seated in bearing cups. Rotational torque on the gauge assembly should be 2.2 Nm (20 lb-in) with new bearings. Final position should be approximately 45 degrees across gauge tube to ensure that gauge block is in-line with gauge tube high point. This area should be used for pinion shim selection. Selection of pinion shim with gauge block not lined up with tube high point will cause improper shim selection and may result in axle noise.
   
   
   
   

   NOTE: Shims must be flat. Do not use dirty, bent, nicked or mutilated shims as a gauge.

5. Use pinion shims as the gauge for shim selection. This will minimize errors in attempting to stack feeler gauge stock together or simple addition errors in calculating correct shim thickness.

   NOTE: The same rear pinion bearing used in this procedure must be used in final assembly of the axle.

6. It is important to feel a slight drag on the shim for correct selection. Do not attempt to force the shim between the gauge block and the gauge tube. This will minimize selection of a shim thicker than required which results in a deep tooth contact in final assembly of integral axles.

   NOTE: A tooth pattern check with the marking compound and road testing is not required when Pinion Depth Gauge Set T79P-4020-A is used.

7. Place the selected shim(s) on pinion shaft and press pinion bearing until firmly seated onshaft.