Axle Seal - Rear

This procedure covers removal and replacement of the rear axle shaft seal on a 2015-2020 Ford F-150 with 5.0L V8 and rear-wheel drive, requiring differential cover removal and fluid replacement.

Warnings

Tools required

Parts

• Rear axle shaft seal × 1 — Use OEM specification
• Differential cover gasket or RTV silicone × 1 — Use OEM specification or Motorcraft TA-30

Fluids

• Motorcraft 75W-140 Synthetic Gear Oil — 2.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks in front of both front wheels
3. Loosen rear wheel lug nuts while vehicle is on ground
4. Raise rear of vehicle and support securely on jack stands at frame contact points
5. Remove both rear wheels completely
6. Position drain pan under rear differential

Procedure

1. 1

   Remove differential cover
   Using appropriate socket, loosen all differential cover bolts in a crisscross pattern, leaving two bolts at the top partially engaged. Carefully pry the cover away from the housing at the bottom to break the seal and allow gear oil to drain into the pan. Once drained, remove the remaining bolts and cover. Retain the cover for cleaning and reinstallation.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
2. 2

   Clean differential housing and cover
   Remove all old gasket material from both the differential housing mating surface and the cover using a plastic gasket scraper. Clean surfaces thoroughly with brake cleaner and shop rags. Inspect the cover for cracks or warping; replace if damaged. Use a wire brush to clean bolt threads in the housing.
   ⚠Do not use metal scrapers on aluminum housing surfaces as this can create leaks. Use only plastic or brass tools.
3. 3

   Remove differential pinion shaft lock bolt
   Locate the pinion shaft lock bolt on the differential carrier inside the housing. Remove this bolt completely and set aside. The pinion shaft should now be able to slide out partially.
   ℹ️Some gear oil may drain when removing this bolt. Keep drain pan positioned appropriately.
4. 4

   Remove pinion shaft
   Slide the differential pinion shaft out of the carrier. You may need to rotate the driveshaft slightly to align the shaft for removal. Set the pinion shaft aside in a clean area to prevent dirt contamination.
   ⚠Do not rotate the driveshaft excessively or allow the axle shafts to fall out of position during this step.
5. 5

   Push in axle shaft and remove C-clip
   Push the axle shaft on the affected side inward toward the center of the differential. This will expose the C-clip retainer that locks the axle shaft in place. Using a magnetic pick or needle-nose pliers, carefully remove the C-clip from the axle shaft groove. Store the C-clip in a safe location for reinstallation.
   ⚠C-clips can easily drop and be lost inside the differential housing. Work carefully and have a magnetic retrieval tool ready.
6. 6

   Remove axle shaft
   Carefully pull the axle shaft straight out of the axle tube and differential housing. Avoid damaging the seal bore during removal. Inspect the axle shaft bearing surface and splines for wear or damage. Replace the axle shaft if grooves, pitting, or excessive wear are present.
   ℹ️If the axle shaft does not pull out easily, verify the C-clip was completely removed and the shaft is fully pushed in before attempting removal.
7. 7

   Remove old axle seal
   Using a slide hammer with seal puller attachment, hook onto the inner lip of the old axle seal. Apply steady pulling force to extract the seal from the axle tube. Alternatively, carefully pry out the seal using appropriate tools, taking care not to damage the seal bore surface in the axle housing.
   ⚠Do not score or gouge the seal bore surface as this will cause the new seal to leak. Use appropriate seal removal tools only.
8. 8

   Clean and inspect seal bore
   Thoroughly clean the axle seal bore with brake cleaner and a shop rag. Inspect the bore for scratches, corrosion, or damage that could prevent proper seal seating. Light surface rust can be removed with fine emery cloth; deep scoring requires housing replacement or professional repair.
   ℹ️The seal bore must be smooth and clean for the new seal to function properly.
9. 9

   Install new axle seal
   Lightly coat the outer diameter of the new seal with gear oil. Position the seal squarely in the bore with the seal lip facing inward toward the differential. Using a seal driver or appropriately sized socket that contacts only the outer edge of the seal, drive the seal into the bore until it is fully seated and flush with the housing face. Apply even pressure and tap progressively around the seal circumference.
   ⚠Do not drive the seal in at an angle or strike the seal face directly, as this will damage the seal and cause leaks.
10. 10

    Reinstall axle shaft
    Coat the axle shaft splines and bearing surface lightly with gear oil. Carefully slide the axle shaft into the axle tube, guiding it through the new seal and into the differential carrier. Align the splines and push the shaft in until it engages with the side gear. Push the shaft inward as far as it will go to expose the C-clip groove.
    ⚠Be careful not to damage the new seal lip during axle shaft installation. Guide the shaft straight in without angling.
11. 11

    Install C-clip and secure axle shaft
    Install the C-clip into the groove at the inner end of the axle shaft, ensuring it is fully seated in the groove. Pull the axle shaft outward to engage the C-clip with the side gear. Verify the axle shaft is securely retained and cannot be pulled out.
    ℹ️The C-clip must be fully seated in the groove and engaged with the side gear for safe operation.
12. 12

    Reinstall pinion shaft and lock bolt
    Slide the differential pinion shaft back into the carrier, aligning it with the pinion gears. Rotate the driveshaft if necessary to align the lock bolt hole. Install the pinion shaft lock bolt and tighten securely. Verify the pinion shaft is properly seated and the lock bolt is tight.
    ⚠The pinion shaft must be fully inserted and aligned before installing the lock bolt.
13. 13

    Install differential cover with new gasket
    If using RTV silicone, apply a continuous 3-4mm bead around the cover mounting surface, circling all bolt holes. If using a pre-cut gasket, position it on the cover. Position the cover onto the differential housing, aligning all bolt holes. Install all differential cover bolts hand-tight first, then tighten in a crisscross pattern to specified torque.
    ℹ️If using RTV silicone, allow 15-20 minutes for initial setup before filling with gear oil, or follow manufacturer instructions.
    Torque spec

    Differential Cover Bolts35 Nm (26 lb-ft)
14. 14

    Fill differential with gear oil
    Locate the differential fill plug on the front of the housing (if equipped) or fill through the cover. Add Motorcraft 75W-140 Synthetic Gear Oil until the level reaches the bottom of the fill plug hole or according to manufacturer specifications (approximately 2.0-2.5 quarts). Install fill plug if applicable. Verify no leaks around the cover.
    ⚠Use only the specified gear oil type. Incorrect fluid can cause differential damage and void warranties.
15. 15

    Reinstall wheels and lower vehicle
    Reinstall both rear wheels, threading lug nuts by hand initially. Lower the vehicle until the wheels just contact the ground. Torque all wheel lug nuts to specification in a star pattern. Fully lower the vehicle and remove jack stands.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all differential cover bolts are torqued to specification in proper sequence
2. Verify differential is filled to proper level with correct gear oil specification
3. Double-check that C-clip is properly installed and axle shaft cannot pull out
4. Confirm no gear oil leaks are present around differential cover or new axle seal

Verification

• Start the engine and verify no unusual noises from the rear differential
• Test drive the vehicle at low speed, checking for proper operation and no leaks
• After 50-100 miles of operation, re-inspect the differential cover and axle seal area for any signs of leakage
• Check differential fluid level after test drive and top off if necessary
• Verify no gear oil on the inside of the rear wheel or brake components

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