Replace the front axle shaft seal on the passenger or driver side to stop differential fluid leaks at the axle shaft interface.

Warnings

Tools required

Parts

• Front axle shaft seal × 1 — Use OEM specification
• Axle nut (staked type) × 1 — Use OEM specification if staked type
• Differential cover gasket or RTV sealant × 1 — Motorcraft TA-357 RTV or use OEM gasket

Fluids

• 75W-90 GL-5 Gear Oil — 1.5 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Place wheel chocks behind rear wheels
3. Loosen front wheel lug nuts while vehicle is on ground
4. Break loose the front axle nut with breaker bar and 36mm socket (extremely tight at 250 Nm)
5. Raise and support front of vehicle on jack stands at frame rails
6. Remove front wheel on side being serviced

Procedure

1. 1

   Remove axle nut
   Remove the 36mm axle nut completely from the end of the halfshaft. If nut is staked, the stake must be straightened first. Discard the old nut if it was staked as it cannot be reused.
2. 2

   Disconnect CV joint from axle shaft
   Locate the inner CV joint where it connects to the front differential stub shaft. Remove the 6 E14 Torx bolts securing the CV joint to the axle shaft flange. Support the halfshaft to prevent it from hanging on the outer CV joint.
   Torque spec

   CV Bolts70 Nm (52 lb-ft)
3. 3

   Remove halfshaft from hub
   Pull the outer end of the halfshaft out of the wheel hub/bearing assembly. If it is stuck, use a soft mallet to tap on the end while pulling outward. Once free, carefully maneuver the entire halfshaft assembly out from under the vehicle. Be prepared for residual gear oil to drain from the differential opening.
4. 4

   Drain remaining differential fluid
   Position drain pan under the differential. Remove the differential cover bolts and carefully pry the cover off to drain remaining fluid. Clean the cover and mounting surface thoroughly with a wire brush and shop rags.
   ⚠Gear oil may be hot if vehicle was recently driven
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
5. 5

   Remove old axle seal
   Using a seal puller or slide hammer with hook attachment, carefully extract the old axle seal from the differential housing. Work evenly around the seal to avoid damaging the bore. Inspect the bore for any scoring or damage that could cause the new seal to leak.
6. 6

   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, carefully drive the seal into place until it seats flush with the housing. Do not strike the seal face directly.
   ⚠Ensure seal is driven in straight and square to prevent leaks; a cocked seal will fail immediately
7. 7

   Reinstall differential cover
   Install a new gasket or apply a continuous 3-4mm bead of RTV sealant to the differential cover mating surface. Install the cover and thread in all bolts finger tight. Tighten the differential cover bolts in a star pattern to specification.
   ℹ️If using RTV, allow 15 minutes cure time before filling with fluid
   Torque spec

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

   Reinstall halfshaft into hub
   Coat the splines of the outer halfshaft with a thin layer of clean gear oil. Guide the halfshaft through the steering knuckle and push firmly into the wheel hub until fully seated. Install the axle nut finger tight to hold the shaft in position.
9. 9

   Connect CV joint to differential
   Align the inner CV joint with the differential stub shaft flange. Install all 6 E14 CV bolts and tighten in a star pattern to specification.
   Torque spec

   CV Bolts70 Nm (52 lb-ft)
10. 10

    Torque axle nut
    With the halfshaft fully connected at both ends, torque the 36mm axle nut to specification. If using a staked-type nut, use a punch and hammer to stake the nut collar into the halfshaft groove. If using a castellated nut, install a new cotter pin.
    ⚠Have an assistant apply brakes or use a pry bar to prevent hub rotation while torquing axle nut
    Torque spec

    Axle Nut250 Nm (184 lb-ft)
11. 11

    Fill differential with fluid
    Locate the differential fill plug on the front of the differential housing. Remove the fill plug and add 75W-90 GL-5 gear oil until fluid reaches the bottom of the fill hole (approximately 1.5 quarts). Reinstall fill plug. Verify no leaks around the new seal or differential cover.
    ℹ️Vehicle must be level for accurate fluid level; overfilling can cause seal failure
12. 12

    Reinstall wheel
    Install the wheel and thread lug nuts by hand. Lower the vehicle until the tire just contacts the ground. Torque lug nuts in a star pattern to specification. Fully lower vehicle and remove jack stands.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to specification and no tools are left under vehicle
2. Wipe down differential housing and axle area to make leak detection easier during verification

Verification

• Start the engine and shift through all gears including 4WD if equipped
• Turn steering lock to lock while stationary to verify CV joint operation
• Test drive vehicle for 10-15 minutes, including turns in both directions
• Re-check differential fluid level on level ground after test drive
• Inspect axle seal area and differential cover for any signs of leakage
• Verify no unusual noises from CV joints or differential during operation

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