Differential Service

This procedure drains and refills the rear differential with fresh gear oil, ensuring proper lubrication and longevity of the rear axle components.

Warnings

Tools required

Parts

• Drain plug washer × 1 — Use OEM specification
• RTV silicone sealant × 1 — Motorcraft TA-30 or equivalent

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 recently driven, or warm to operating temperature for optimal draining
3. Chock front wheels to prevent vehicle movement
4. Gather all tools, new drain plug washer, RTV sealant, and fresh gear oil

Procedure

1. 1

   Access the differential
   Position drain pan under the rear differential housing. Locate the drain plug on the bottom of the differential housing and the fill plug on the rear face of the housing.
2. 2

   Remove fill plug first
   Using a 3/8 inch ratchet, loosen and remove the fill plug from the rear of the differential housing. This ensures you can refill the differential after draining. If the fill plug cannot be removed, do not proceed with draining.
   Torque spec

   Fill Plug47 Nm (35 lb-ft)
3. 3

   Drain differential fluid
   Remove the drain plug from the bottom of the differential housing. Allow all fluid to drain completely into the drain pan, which may take 5-10 minutes. Inspect drained fluid for metal particles or abnormal debris.
   ⚠Fluid may be hot if differential was warmed to operating temperature. Avoid contact with skin.
   Torque spec

   Drain Plug47 Nm (35 lb-ft)
4. 4

   Inspect and clean drain plug
   Examine the drain plug and magnetic tip (if equipped) for excessive metal particles. Clean the plug threads with brake cleaner. Discard the old copper washer and install a new washer onto the drain plug.
5. 5

   Reinstall drain plug
   Thread the drain plug with new washer into the differential housing by hand until snug, then torque to specification using a torque wrench.
   Torque spec

   Drain Plug47 Nm (35 lb-ft)
6. 6

   Refill differential with gear oil
   Using a fluid transfer pump or squeeze bottle, add Motorcraft 75W-140 Synthetic Gear Oil through the fill plug hole. Fill until fluid begins to drip from the fill hole, indicating proper level (approximately 2.0 quarts). Allow fluid to settle for 1-2 minutes and top off if needed.
7. 7

   Reinstall fill plug
   Clean the fill plug threads with a clean rag. Thread the fill plug into the housing by hand until snug, then torque to specification using a torque wrench.
   Torque spec

   Fill Plug47 Nm (35 lb-ft)
8. 8

   Clean work area and inspect for leaks
   Wipe down the differential housing to remove any spilled gear oil. Remove drain pan and lower the vehicle if raised. Start the engine and allow it to idle, then check around both plugs for any signs of leakage.

Reassembly

1. Ensure both drain and fill plugs are torqued to specification
2. Wipe all excess fluid from differential housing exterior
3. Dispose of used gear oil properly at a recycling center or auto parts store

Verification

• Check that no fluid is leaking from drain plug or fill plug after engine has run for several minutes
• Test drive vehicle and listen for any abnormal differential noises
• After test drive, recheck both plugs for leaks with vehicle on level ground
• Verify proper fluid level by briefly removing fill plug - fluid should be at the bottom of the fill hole threads

Related trouble codes on this vehicle

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