Axle Shaft - Rear

This procedure covers the removal and replacement of the rear axle shaft on a 2021-2024 Ford F-150 with 3.5L EcoBoost engine and rear-wheel drive configuration.

Warnings

Tools required

Parts

• Rear axle shaft assembly × 1 — Use OEM specification for specific axle ratio
• Differential cover gasket × 1 — Use OEM specification
• Axle shaft seal × 1 — Use OEM specification
• Axle shaft bearing (if damaged) × 1 — Use OEM specification

Fluids

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

Preparation

1. Park vehicle on level ground, engage parking brake, and place transmission in Park
2. Chock front wheels securely
3. Loosen wheel lug nuts on the rear wheel corresponding to the axle shaft being replaced (do not remove)
4. Raise rear of vehicle with floor jack and support securely on jack stands under frame rails
5. Remove rear wheel and tire assembly
6. Position drain pan under differential
7. Allow differential to cool if vehicle was recently operated

Procedure

1. 1

   Drain differential fluid
   Remove the differential cover bolts in a crisscross pattern, leaving two bolts at the top loosely threaded. Carefully pry cover away from housing to break seal and allow fluid to drain into pan. Once drained, remove remaining bolts and cover. Clean mating surface on differential housing with scraper and wire brush.
   Torque spec

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

   Remove differential pinion shaft lock bolt
   Locate the differential pinion shaft lock bolt at the rear of the differential carrier. Remove this bolt completely and set aside. This bolt secures the cross-pin shaft that retains the axle shafts.
   ℹ️Keep track of this bolt as it is critical for reassembly. Some models may use a locking tab that must be bent back before removal.
3. 3

   Remove differential pinion shaft
   With the lock bolt removed, push or tap the differential pinion shaft (cross-pin) out of the differential carrier. This shaft passes through the spider gears and must be completely removed to access the C-clip retainers on the axle shafts. Use care not to damage the shaft or carrier bore.
   ⚠Do not rotate the wheels or driveshaft once the pinion shaft is removed, as the spider gears may fall out of position.
4. 4

   Remove axle shaft C-clip
   Push the axle shaft inward toward the center of the differential. This will expose the C-shaped retaining clip at the inner end of the axle shaft splines. Use a magnetic pick or small screwdriver to remove the C-clip from the groove in the axle shaft. Store the C-clip safely if reusing.
   ℹ️If the C-clip cannot be accessed, ensure the axle shaft is pushed in far enough and that the pinion shaft is fully removed.
5. 5

   Remove axle shaft from housing
   With the C-clip removed, carefully pull the axle shaft straight out of the axle housing tube. The shaft should slide out with steady, even pressure. If resistance is encountered, use a slide hammer with axle shaft adapter attached to the wheel studs to extract the shaft. Once shaft begins to move, continue pulling by hand to remove completely.
   ⚠Axle shaft weighs approximately 20-30 pounds. Maintain secure grip to prevent dropping and injury.
6. 6

   Inspect and replace axle seal and bearing
   With the axle shaft removed, inspect the axle seal at the outer end of the housing tube. If the seal shows any signs of leakage, damage, or if the axle shaft is being replaced, remove the old seal using a seal puller or pry bar. Inspect the bearing inside the housing tube; if worn or damaged, use a bearing puller to remove it. Install new bearing (if needed) using appropriate driver, then install new axle seal with seal driver, ensuring it seats flush and square in the housing bore.
   ⚠Do not damage the seal bore in the axle housing during seal removal. A damaged bore will cause persistent leaks.
7. 7

   Prepare and install new axle shaft
   Lightly coat the axle shaft seal contact area and splines with clean gear oil. Carefully insert the new or replacement axle shaft into the housing tube, taking care not to damage the seal lip. Push the shaft in until it reaches the differential, ensuring the splined end engages with the differential side gear. Rotate the shaft slightly if needed to align splines.
   ℹ️Do not force the axle shaft. If excessive resistance is felt, remove and check for seal damage or misalignment.
8. 8

   Install axle shaft C-clip
   Push the axle shaft fully inward toward the differential center. Install the C-clip into the groove at the inner end of the axle shaft splines, ensuring it seats completely in the groove. Pull outward on the axle shaft to verify the C-clip is properly seated and the shaft is retained.
   ⚠Verify the C-clip is fully seated in the axle shaft groove. An improperly seated C-clip can allow the axle shaft to walk out during operation.
9. 9

   Reinstall differential pinion shaft and lock bolt
   Align the hole in the differential pinion shaft with the lock bolt hole in the carrier. Insert the pinion shaft through the differential case and spider gears, ensuring proper alignment. Install the pinion shaft lock bolt and tighten securely. If equipped with a locking tab, bend the tab over the bolt head to prevent loosening.
10. 10

    Install differential cover
    Clean the differential cover thoroughly and inspect for warping or damage. Apply a continuous bead of RTV silicone gasket maker to the cover flange (or install new gasket per manufacturer instructions). Position the cover on the differential housing and install all cover bolts hand-tight. Tighten bolts in a crisscross pattern to the specified torque. Allow RTV to cure per manufacturer instructions before filling with fluid.
    ℹ️If using RTV, some manufacturers recommend waiting 15-30 minutes before filling with fluid to allow proper curing. Consult RTV product instructions.
    Torque spec

    Differential Cover Bolts35 Nm (26 lb-ft)
11. 11

    Refill differential with gear oil
    Locate the differential fill plug on the front of the differential housing. Remove the fill plug. Using a fluid pump or funnel with extension hose, add Motorcraft 75W-140 Synthetic Gear Oil until fluid level reaches the bottom of the fill hole (fluid should just begin to seep out). Install fill plug and tighten securely. Verify no leaks around differential cover.
    ℹ️Differential capacity is approximately 2.0 quarts, but may vary. Fill to proper level, not by capacity measurement.
12. 12

    Reinstall wheel and lower vehicle
    Install the wheel and tire assembly on the hub. Thread lug nuts by hand to prevent cross-threading. Tighten lug nuts in a star pattern using torque wrench to specification. Lower vehicle carefully from jack stands to the ground. With vehicle weight on wheels, perform final torque on lug nuts in star pattern.
    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. Check that wheel lug nuts are torqued in star pattern with vehicle weight on ground
4. Inspect for any fluid leaks around differential cover and axle seal

Verification

• Start vehicle and verify no abnormal noises from rear differential
• Test drive vehicle at low speed, confirming smooth operation with no clicking, grinding, or vibration from rear axle
• After test drive, re-inspect differential cover and axle seal area for any signs of fluid leakage
• After 50-100 miles of operation, recheck differential fluid level and inspect for leaks
• Verify wheel lug nut torque after first 50 miles of driving

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