Inspection Before Disassembly

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

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 damaged bearings or gears.

Ring Gear Backface Runout:

Ring Gear Backface Runout - Rear Anti-Lock Brake Vehicles:

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

4. On E-150 vehicles, set up a dial indicator and check ring gear backlash and ring gear backface runout. On Bronco and F-150 vehicles equipped with rear Antilock brakes, mount Dial Indicator, TOOL-4201-C, or equivalent, on the carrier so the tip of the dial indicator contacts the backface of the ring gear.

NOTE: There is a space provided between the excitor ring and the ring gear for measuring ring gear backface runout. Backlash should be 0.008 inch to 0.015 inch (0.012-0.015 inch preferred) and backface runout should be no more than 0.004 inch.

Ring Gear Backlash:

5. A contact pattern is not an acceptable guide to check for noise. Proper gear set assembly must be checked using the pinion depth gauge Tool T79P-4020-A which shows the correct pinion shim required.