Ring and Pinion Gear Set

Differential ring and pinion gears, bearings, and all associated parts must be cleaned thoroughly before inspecting. Check the gears for unusual wear patterns, scoring, chipped or damaged teeth.

Differential ring gear backlash measurement.

Ring and pinion gears come as a set. If one of them is damaged, out of specs, or worn, both must be replaced. When a vehicle pulls a heavy load, the pinion gear tends to ride on the outer portion of the ring gear. This will cause excessive scoring, evident on the outer edges of the ring gear.

Gearsets without timing marks are considered hunter sets. Typical ring and pinion gears have notches and painted marks for proper alignment. Installing a set incorrectly will result in noise and premature wear. Ring gear runout is the amount of warpage in the ring gear and is measured with a dial indicator mounted on the differential case. If the ring gear is warped, it’s important to find the cause. Though this warpage is typically due to wear, the differential case mounting surface should be checked. This is also done with a dial gauge. Worn side bearings will also cause a ring gear to warp.

Special depth micrometers are used to achieve proper pinion gear depth. The pinion gear depth is adjusted using shims placed in the housing. This adjustment determines the mesh of the pinion into the ring gear. Adding shims will increase the depth of the pinion shaft, and removing shims will decrease the depth.