Differential Cover Gasket

This procedure replaces the rear differential cover gasket on a 2015-2020 Ford F-150 with 5.0L V8, requiring draining and refilling the differential fluid.

Warnings

Tools required

Parts

• Rear differential cover gasket × 1 — Use OEM Ford gasket or quality aftermarket
• Rear differential cover bolts (if corroded) × 10 — OEM replacement if needed

Fluids

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

Preparation

1. Park vehicle on level ground and engage parking brake
2. Chock front wheels to prevent rolling
3. Allow differential to cool if vehicle was recently driven
4. Raise rear of vehicle with floor jack and support on jack stands at frame rails
5. Ensure adequate working clearance under vehicle (minimum 24 inches recommended)
6. Place drain pan under rear differential cover

Procedure

1. 1

   Locate and clean differential cover
   The rear differential is located at the center of the rear axle. Clean the area around the differential cover bolts using a wire brush to remove dirt and road debris. This prevents contamination when the cover is removed.
2. 2

   Loosen differential cover bolts
   Using a 13mm socket, loosen all differential cover bolts approximately 2-3 turns. Do not fully remove bolts yet. There are typically 10 bolts around the perimeter of the cover. Loosening them gradually allows fluid to begin draining without the cover dropping unexpectedly.
3. 3

   Drain differential fluid
   Position drain pan directly under the differential cover. Remove the bottom bolts first while supporting the cover with one hand. Allow fluid to drain into pan. Once initial flow slows, carefully remove remaining bolts and pull cover away from differential housing. Tilt cover to drain remaining fluid. Expect approximately 2 quarts to drain.
   ⚠Fluid may drain rapidly when bottom bolts are removed. Keep hands and drain pan positioned to catch flow.
4. 4

   Remove old gasket material
   Use a plastic gasket scraper to carefully remove all old gasket material from both the differential housing mating surface and the cover. Take care not to gouge or scratch the metal surfaces as this can cause leaks. Clean both surfaces thoroughly with brake cleaner and wipe dry with shop rags. Inspect for any damage or warping.
   ⚠Do not allow gasket debris to fall into the open differential housing. Cover opening with clean rag if necessary.
5. 5

   Inspect differential internals
   With the cover removed, visually inspect the ring gear and pinion teeth for unusual wear, chips, or metal shavings in the bottom of the housing. Check the magnetic drain plug (if equipped) for excessive metal particles. Minor fine particles are normal, but large chunks indicate potential failure.
6. 6

   Install new gasket and position cover
   Place the new gasket onto the differential cover, aligning all bolt holes. Some gaskets are adhesive-backed and will stick to the cover. Position the cover with gasket against the differential housing, ensuring the gasket stays properly aligned. Start all bolts by hand to prevent cross-threading.
7. 7

   Torque differential cover bolts
   Tighten the differential cover bolts in a criss-cross or star pattern to ensure even gasket compression. Torque all bolts to specification. Work through the pattern at least twice, first to approximately half torque, then to final specification to ensure even seating.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
8. 8

   Refill differential with gear oil
   Locate the fill plug on the front of the differential housing (typically 3/8" square drive plug). Remove the fill plug. Using a fluid pump or funnel with flexible hose, add Motorcraft 75W-140 Synthetic Gear Oil through the fill hole. Fill until fluid reaches the bottom of the fill plug hole (fluid should just begin to seep out). Install and tighten fill plug securely.
   ℹ️If vehicle is equipped with limited-slip differential, add appropriate friction modifier additive per manufacturer specifications.
9. 9

   Lower vehicle and check for leaks
   Remove jack stands and carefully lower the vehicle to the ground. Wipe the differential cover area clean with a rag. Start the engine and let it idle for 1-2 minutes, then shift through all gear ranges. Inspect the cover gasket area for any signs of seepage or leaks.

Reassembly

1. Ensure all differential cover bolts are torqued to specification in a star pattern
2. Verify differential fill plug is securely tightened
3. Dispose of used gear oil properly at a recycling center or auto parts store

Verification

• Check differential cover for any fluid leaks around gasket perimeter
• Verify fill plug is not leaking
• Test drive vehicle for 5-10 minutes, then recheck for leaks with vehicle on level ground
• Monitor differential area for seepage over next 50-100 miles of driving

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