Complete removal and replacement of the front differential assembly on a 4WD F-150, including driveshaft disconnection, axle shaft removal, and differential mounting.

Warnings

Tools required

Parts

• Front differential assembly × 1 — Use OEM specification
• Differential cover gasket × 1 — Use OEM specification
• Axle shaft seals × 2 — Use OEM specification
• Cotter pins or new axle nuts (if staked type) × 2 — Use OEM specification
• Front driveshaft U-joint strap hardware × 1 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 1.5 qt

Preparation

1. Park vehicle on level ground and set parking brake
2. Loosen front wheel lug nuts while vehicle is on ground
3. Raise front of vehicle and support securely on jack stands at frame rail points
4. Remove both front wheels
5. Place drain pan under front differential
6. Allow vehicle to cool if recently driven to avoid hot gear oil

Procedure

1. 1

   Drain front differential fluid
   Locate the differential drain plug on the bottom of the differential housing (if equipped) or remove the differential cover bolts. Remove drain plug or loosen cover bolts gradually starting from the bottom to allow fluid to drain. Allow all gear oil to drain completely into drain pan. If removing cover, break seal carefully with gasket scraper after most bolts are removed.
   Torque spec

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

   Mark and disconnect front driveshaft
   Use paint or marker to mark the driveshaft yoke position relative to the differential pinion flange for proper alignment during reinstallation. Remove the four U-joint strap bolts securing the driveshaft to the front differential pinion flange. Support the driveshaft and carefully separate it from the differential. Secure driveshaft out of the way with wire or bungee cord to prevent damage to CV joint at transfer case end.
   ℹ️Do not allow driveshaft to hang unsupported as this can damage the CV joint at the transfer case.
   Torque spec

   Driveshaft U-Joint Straps20 Nm (15 lb-ft)
3. 3

   Remove axle shaft retaining hardware
   On each side, remove the cotter pin (if equipped) or use a punch and hammer to unstake the axle nut. Use a breaker bar with appropriate socket to loosen and remove both front axle nuts. These nuts require significant force to remove. Keep nuts if they are the staked type and not damaged, otherwise use new nuts for reassembly.
   ⚠Axle nuts are torqued to 250 Nm and may require significant force to break loose. Ensure vehicle is securely supported before applying force.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)
4. 4

   Disconnect CV axle shafts from differential
   Locate the six bolts on each side that secure the CV shaft flanges to the differential output flanges. Mark the orientation of each CV shaft to its corresponding differential flange. Remove all six bolts from each side. Carefully pull the hub assemblies outward to separate the CV shafts from the differential. Support the CV shafts and secure them to the suspension or frame to prevent damage. Do not allow them to hang freely.
   Torque spec

   CV Bolts76 Nm (56 lb-ft)
5. 5

   Disconnect differential electrical connectors
   Locate and disconnect any electrical connectors attached to the differential. This may include a differential temperature sensor or electronic locking differential connector (if equipped with electronic locker). Press the release tabs and carefully separate connectors. Note connector positions for reassembly.
   ℹ️Not all F-150 configurations have electronic differential sensors. Verify your specific vehicle configuration.
6. 6

   Support differential with transmission jack
   Position a transmission jack or differential jack under the center of the front differential housing. Raise the jack until it just contacts the differential and secure it with a strap or chain. The differential should be supported but not lifting the vehicle. Adjust jack position to ensure differential is balanced and stable.
   ⚠️The differential assembly weighs 80-90 lbs and will drop when mounting bolts are removed. Ensure jack is properly positioned and secured before removing mounting hardware.
7. 7

   Remove differential mounting bolts
   Locate the mounting bolts securing the differential to the front crossmember and suspension components. There are typically 4-6 mounting bolts depending on configuration. Remove all mounting bolts while supporting the differential with the transmission jack. Keep track of bolt locations as they may be different lengths.
   ⚠Have an assistant help guide the differential as the final bolts are removed to prevent it from shifting on the jack.
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
8. 8

   Lower and remove differential assembly
   With all mounting bolts removed, slowly and carefully lower the transmission jack while guiding the differential away from the CV shaft openings and any remaining connections. The differential may need to be tilted or rotated to clear the frame and suspension components. Once clear, lower completely and remove from under vehicle. Inspect all mounting points and clean surfaces for reinstallation.
   ⚠Move slowly and check clearances on all sides. The differential may catch on brake lines, ABS sensors, or suspension components during removal.
9. 9

   Prepare new differential for installation
   If installing a used differential, drain and inspect internal condition. Replace axle shaft seals in both output shaft locations. Clean all mating surfaces on the new differential. If the differential is supplied dry, install the fill and drain plugs. Apply a thin bead of RTV silicone to the differential cover mating surface if cover was removed, then install cover with new gasket.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
10. 10

    Install differential assembly
    Position the new differential on the transmission jack and raise it into position under the vehicle. Align the differential with the mounting points on the crossmember and suspension. Carefully navigate the differential into place, ensuring CV shaft openings align properly. Thread in all mounting bolts by hand before tightening any. Once all bolts are started, torque mounting bolts to specification in a cross pattern.
    ℹ️Have an assistant help align the differential during installation to prevent cross-threading mounting bolts.
    Torque spec

    Mounting Bolts34 Nm (25 lb-ft)
11. 11

    Reconnect CV axle shafts
    Clean the CV shaft flanges and differential output flanges with a wire brush. Align the CV shafts with their marked positions on the differential output flanges. Install all six bolts per side by hand, ensuring proper engagement. Torque CV bolts to specification in a star pattern. Apply medium-strength thread locker to bolt threads before installation.
    Torque spec

    CV Bolts76 Nm (56 lb-ft)
12. 12

    Install axle shaft retaining nuts
    Clean the axle shaft threads and hub threads. Install the axle nuts and torque to specification using a torque wrench. If using staked nuts, stake the nut collar into the axle shaft groove using a punch and hammer. If using cotter pin type, install a new cotter pin and bend the ends to secure.
    ⚠Ensure axle shafts are fully seated in hubs before torquing nuts. Verify proper engagement by checking that shaft does not move in or out.
    Torque spec

    Axle Nut250 Nm (184 lb-ft)
13. 13

    Reconnect front driveshaft
    Align the driveshaft yoke with the differential pinion flange using the alignment marks made during disassembly. Install the four U-joint strap bolts and torque evenly to specification in a cross pattern. Verify driveshaft rotates freely without binding.
    ℹ️Proper driveshaft alignment is critical. Misalignment can cause vibration and premature U-joint failure.
    Torque spec

    Driveshaft U-Joint Straps20 Nm (15 lb-ft)
14. 14

    Fill differential with gear oil
    Locate the differential fill plug on the side of the housing. Remove the fill plug and use a fluid pump to add 75W-90 GL-5 gear oil until it reaches the bottom of the fill hole (approximately 1.5 quarts). Oil should just begin to seep out of the fill hole when at proper level. Install and tighten fill plug.
    ℹ️Some differentials may require limited-slip additive if equipped with limited-slip differential. Verify your specific differential type before filling.
15. 15

    Reinstall wheels and final checks
    Reconnect any electrical connectors that were disconnected. Install both front wheels and hand-tighten lug nuts. Lower vehicle to ground and torque wheel lug nuts to specification in a star pattern. Remove jack stands and lower vehicle completely. Check all fasteners for proper torque and verify no fluid leaks.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all electrical connectors are properly seated and locked
2. Verify all drain and fill plugs are tight and not leaking
3. Double-check that CV shaft bolts are torqued to specification as these are critical safety components
4. Confirm driveshaft U-joint straps are properly torqued and aligned

Verification

• Start vehicle and verify no unusual noises from front differential area
• Test drive vehicle in 4WD mode at low speed in a safe area to verify proper engagement
• Check for gear oil leaks around differential cover, axle seals, and fill/drain plugs after test drive
• Verify smooth operation during turns and no binding or clicking from CV joints
• Re-check differential fluid level after test drive and top off if necessary
• Inspect all mounting bolts and CV shaft bolts after 50-100 miles of driving to ensure they remain tight

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