Inspection Before Disassembly

The differential case assembly and drive pinion should be inspected before they are removed from the carrier casting. These inspections can help find the cause of the concern and determine the correction needed.

1. Wipe the lubricant from the internal working parts and visually inspect the parts for wear and/or damage.

2. Rotate the gears to see if there is any roughness which would indicate worn or damaged bearings or gears.

3. Check the ring gear teeth for signs of scoring, abnormal wear or nicks/chips.




FIG. 16 Ring and Pinion Gear Backlash Check

FIG. 17 Ring Gear Runout Check-Vehicles Not Equipped with Rear Antilock Brakes

FIG. 18 Ring Gear Back face Runout Check-Vehicles Equipped with Rear Antilock Brakes
4. Set up a dial indicator (Figs. 16,17 and 18), and check ring gear backlash and ring gear backface runout.

NOTE: On F-Series and Bronco vehicles equipped with Rear Antilock Brakes (RAB), mount Dial Indicator with Bracketry, TOOL-4201 -C, or equivalent on the carrier so the tip of the dial indicator contacts the backface of the ring gear (Fig. 17). There is a space provided between the excitor ring and the ring gear for measuring ring gear backface runout.

5. Proper gear set assembly must be checked using the Pinion Depth Gauge T79P-4020-A or equivalent which shows correct pinion shim required to assure acceptable running condition.