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.
The 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.
Gear sets without timing marks are considered hunter sets. Typical ring and pinion gears will have notches and painted marks on them for proper alignment. Installing a set incorrectly may 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 done with a dial gauge the same way as the ring gear. 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 while removing shims will decrease the depth.
Pinion bearing preload is adjusted by tightening the pinion nut to a specified torque. By tightening the pinion nut the collapsible pinion spacer is being crushed. If this collapsible spacer is over tightened it must be replaced. Tighten this nut in steps checking it with an inch pound torque wrench until acquiring the specified torque. Solid spacers are used but typically found in heavy duty applications.
