Differential Drive Pinion Gear and Ring Gear

Differential Drive Pinion Gear and Ring Gear Description and Operation

Drive Pinion and Ring Gear Identification

Production drive pinion and ring gears are manufactured by using a 2 cut or a 5 cut method. The 2 cut drive pinions and ring gears can be identified by having a groove cut into the outside edge of the ring gear and a ring on the stem of the drive pinion. The gear tooth contact patterns that are produced from each style of gear set differ slightly. A 2 cut gear will produce a pattern that is bias from the toe to the heel of the tooth (drive side), while a 5 cut gear will produce a square pattern from the toe to the heel of the (drive side). When diagnosing the gear tooth contact pattern, regardless of what type of gear set it is, a correct pattern will be centered within the area of the tooth, from the toe to the heel and from the top to the bottom. For the proper gear tooth wear pattern, refer to Gear Tooth Contact Pattern Inspection Gear Tooth Contact Pattern Inspection.

Test Procedure

1. Using the appropriate cleaning solvent, remove the lubricant from the differential housing and from the teeth of the ring gear.




2. Using a medium stiff brush, sparingly apply gear marking compound to all of the ring gear teeth. Refer to Adhesives, Fluids, Lubricants, and Sealers Fluid Type Specifications.

Caution: Refer to Fastener Caution Fastener Caution.

3. Torque the differential bearing caps.

* Tighten the differential bearing caps. For the 8.6 inch axle, tighten the bearing caps to 75 Nm (55 lb ft)
* For the 9.5 inch LD axle, tighten the bearing caps to 95 Nm (63 lb ft)
* For the 10.5 inch axle, tighten the bearing caps to 185 Nm (136 lb ft)

4. Apply the park brake until the torque load is 14 Nm (10 lb ft) is required to rotate the pinion.

Note: Avoid rotating the ring gear excessively, this could give a false contact pattern.

5. Using the appropriate size wrench, slowly rotate the drive pinion flange/yoke 3 complete revolutions clockwise.
6. Slowly rotate the drive pinion flange/yoke 3 complete revolutions counter-clockwise.
7. Observe the contact pattern on the teeth. Refer to Gear Tooth Contact Pattern Inspection Gear Tooth Contact Pattern Inspection.