Differential Fluid Change - Rear

This procedure drains and refills the rear differential with fresh synthetic gear oil to maintain proper lubrication and extend component life.

Warnings

Tools required

Parts

• Rear differential cover gasket × 1 — Use OEM Ford gasket or RTV silicone

Fluids

• Motorcraft 75W-140 Synthetic Gear Oil — 2 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow differential to cool if vehicle was recently driven
3. Raise and support rear of vehicle with jack stands on frame rails
4. Verify you have correct fluid specification (75W-140 synthetic, NOT 75W-90)

Procedure

1. 1

   Locate and clean differential cover
   Position yourself under the rear axle. The differential cover is a cast aluminum housing at the center of the rear axle. Clean the area around the cover with a wire brush and brake cleaner to prevent contamination during service.
2. 2

   Remove differential cover bolts
   Using a 3/8 inch drive ratchet and appropriate socket, loosen all differential cover bolts in a criss-cross pattern. Leave the top two bolts partially threaded to prevent the cover from falling when fluid drains.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
3. 3

   Drain differential fluid
   Position drain pan under the differential cover. Carefully remove the remaining top bolts and allow the cover to tilt down, draining fluid into the pan. Once flow stops, remove the cover completely and allow all remaining fluid to drain. Inspect the drained fluid for excessive metal particles or debris.
   ⚠Fluid will flow quickly once cover is loosened. Keep hands clear and position drain pan to catch all fluid.
4. 4

   Inspect and clean cover and housing
   Inspect the differential cover magnet (if equipped) for metal shavings, which is normal. Remove and clean the magnet. Use a gasket scraper to remove all old gasket material from both the differential housing mating surface and the cover. Clean both surfaces thoroughly with brake cleaner and a shop rag until completely free of oil and debris.
5. 5

   Install new gasket on cover
   Install the new differential cover gasket onto the cover. If using RTV silicone instead of a pre-formed gasket, apply a continuous 1/8 inch bead around the entire perimeter of the cover, circling all bolt holes. Allow RTV to set for 5-10 minutes before installation.
6. 6

   Reinstall differential cover
   Align the differential cover with the housing and start all bolts by hand to ensure proper threading. Tighten bolts in a criss-cross pattern to the specified torque in two stages: first to 15 ft-lb, then to final torque of 26 ft-lb (35 Nm).
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
7. 7

   Refill differential with fresh fluid
   Locate the fill plug on the differential housing (typically on the front or rear face of the housing). Remove the fill plug. Using a fluid pump or funnel with long hose, add 2.0 quarts of Motorcraft 75W-140 synthetic gear oil through the fill hole. Fluid is at proper level when it begins to seep from the fill hole.
8. 8

   Reinstall fill plug and verify
   Clean the fill plug threads and reinstall the plug, tightening securely by hand plus 1/4 turn. Wipe down the entire differential housing to remove any spilled fluid. Inspect the cover gasket area for any signs of leakage.

Reassembly

1. Lower vehicle from jack stands
2. Dispose of used differential fluid at appropriate recycling facility
3. If using RTV silicone, allow 24 hours cure time before driving

Verification

• Start vehicle and verify no warning lights are illuminated
• Test drive vehicle for 5-10 miles, including several turns in both directions
• Re-inspect differential cover for leaks after test drive, especially around gasket sealing area
• Check fluid level at fill plug after test drive to ensure proper fill level is maintained

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle