Complete removal and replacement of the rear differential assembly on a 2011-2014 Ford F-150 3.5L EcoBoost 4WD, including driveshaft disconnect, axle separation, and fluid refill.

Warnings

Tools required

Parts

• Rear differential assembly (if replacing complete unit) × 1 — Use OEM specification for 9.75 inch ring gear
• Differential cover gasket × 1 — Use OEM specification
• Axle shaft seals (if replacing differential) × 2 — Use OEM specification
• Cotter pins for axle nuts × 2 — Use OEM specification

Fluids

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

Preparation

1. Park vehicle on level surface and engage parking brake
2. Chock front wheels securely
3. Loosen rear wheel lug nuts while vehicle is on ground
4. Raise vehicle at all four corners and support on jack stands rated for vehicle weight
5. Remove both rear wheels completely
6. Place drain pan underneath rear differential
7. Clean exterior of differential housing and cover to prevent contamination during service

Procedure

1. 1

   Drain differential fluid
   Remove the differential cover bolts in a crisscross pattern to allow fluid to drain. Start with the bottom bolts and work upward. Once fluid begins draining, carefully remove remaining bolts and the cover. Allow all fluid to drain completely into drain pan. Inspect drained fluid for metal particles or contamination.
   Torque spec

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

   Mark and disconnect rear driveshaft
   Use marking paint or chalk to mark the relationship between the driveshaft and rear pinion flange for proper reinstallation alignment. Remove the four U-joint strap bolts at the differential pinion flange. Support the driveshaft and carefully lower it away from the pinion. Secure driveshaft out of the way using wire or mechanics wire to prevent it from hanging freely.
   ⚠Do not allow driveshaft to hang unsupported as this can damage the center support bearing or front U-joint.
   Torque spec

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

   Remove brake calipers and rotors
   Remove the brake caliper mounting bolts on both sides. Support calipers with wire or bungee cords - do not let them hang by brake hoses. Remove brake rotors by pulling them off the hub assembly. If rotors are stuck, use penetrating oil and tap gently with a rubber mallet.
   ⚠Never allow brake calipers to hang by the brake hose as this can damage the hose internally.
4. 4

   Remove axle shaft retaining nuts
   Remove cotter pins from axle shaft nuts. Using a 21mm socket and breaker bar, remove both rear axle shaft retaining nuts. These nuts are torqued to 250 Nm and may require significant force. Discard old cotter pins as new ones must be installed during reassembly.
   ℹ️An impact wrench is highly recommended for this step to avoid rounding the nut.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)
5. 5

   Disconnect axle shafts from differential
   For independent rear suspension (IRS) models, remove the six CV bolts connecting each axle shaft to the differential output flanges. Support the axle shafts and carefully pull them away from the differential. For solid axle models with semi-floating axles, the shafts can be left in the housing during differential removal. Plug or cap the differential outputs to prevent fluid leakage.
   Torque spec

   CV Bolts70 Nm (52 lb-ft)
6. 6

   Disconnect rear differential mounting
   Position transmission jack or floor jack with adapter under the center of the differential housing. Raise jack slightly to support the weight of the differential. Locate and remove all differential mounting bolts connecting the housing to the frame or suspension mounts. On 4WD models, there are typically four main mounting points.
   ⚠️Ensure jack is properly centered and stable before removing mounting bolts. The differential can shift suddenly when the last bolt is removed.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
7. 7

   Remove differential assembly
   With all mounting bolts removed and the assembly supported on the jack, carefully lower the differential. Guide it clear of the vehicle frame and suspension components. Have an assistant help guide the assembly as you lower it to prevent it from binding or shifting on the jack. Once clear, roll the jack and differential assembly out from under the vehicle.
   ⚠The differential assembly is very heavy and awkward to maneuver. Use extreme caution and get assistance.
8. 8

   Inspect and prepare for installation
   Inspect all mounting points, bushings, and brackets on the vehicle frame for damage or excessive wear. Clean mounting surfaces with a wire brush. If installing a replacement differential, transfer any necessary brackets or sensors from the old unit to the new one. Verify the new or rebuilt differential is the correct ratio for your vehicle (check door sticker for axle code).
   ℹ️F-150 EcoBoost models typically use 3.31, 3.55, or 3.73 rear axle ratios. Installing the wrong ratio will cause speedometer errors and potential drivetrain damage.
9. 9

   Install differential assembly
   Position the differential on the transmission jack and carefully raise it into position under the vehicle. Align all mounting points with the frame brackets. Start all mounting bolts by hand before tightening any of them. Once all bolts are started, torque them to specification in a cross pattern to ensure even loading.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
10. 10

    Reconnect axle shafts
    For IRS models, align the axle shaft CV joints with the differential output flanges. Install the CV bolts and torque to specification in a star pattern. For solid axle models, ensure axle shafts are properly seated in the differential carrier. Install new axle shaft retaining nuts and torque to specification, then install new cotter pins through the castellated nut and axle shaft.
    Torque spec

    CV Bolts70 Nm (52 lb-ft)

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

    Reconnect driveshaft
    Raise the rear driveshaft into position, aligning the marks made during disassembly. Install the U-joint strap bolts and tighten evenly to prevent binding. Torque all four strap bolts to specification in a cross pattern.
    ⚠Misalignment of driveshaft marks can cause vibration at highway speeds. Ensure marks are properly aligned.
    Torque spec

    Driveshaft U-Joint Straps20 Nm (15 lb-ft)
12. 12

    Install new differential cover and gasket
    Clean the differential cover mating surface thoroughly with a wire brush and brake cleaner. Install the new gasket on the differential housing (or apply appropriate RTV sealant if specified). Position the cover and install all bolts hand-tight. Torque the cover bolts in a cross pattern to ensure even gasket compression and prevent leaks.
    ℹ️Some differentials use RTV sealant instead of a gasket. Verify the correct sealing method for your specific differential model.
    Torque spec

    Differential Cover Bolts35 Nm (26 lb-ft)
13. 13

    Fill differential with gear oil
    Locate the differential fill plug on the front of the housing (typically requires 3/8 inch square drive or hex key). Remove the fill plug. Using a fluid transfer pump, add Motorcraft 75W-140 Synthetic Gear Oil through the fill hole until fluid begins to drip from the fill hole opening. Install the fill plug and torque to specification if applicable. Total capacity is approximately 2.0 quarts.
    ℹ️For limited slip differentials, add the appropriate friction modifier additive per manufacturer specifications.
14. 14

    Reinstall brake components and wheels
    Reinstall brake rotors onto the hubs. Position brake calipers over the rotors and install caliper mounting bolts, torquing to specification. Install both rear wheels, threading lug nuts by hand initially. Lower the vehicle until the tires just touch the ground (still supported by jack stands). Torque wheel lug nuts to specification in a star pattern.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to proper specifications, particularly axle nuts and driveshaft U-joint straps
2. Verify differential fill level is correct before driving
3. Double-check that brake calipers are properly secured and brake pedal is firm before moving vehicle
4. Confirm no tools or parts were left under the vehicle before final lowering

Verification

• Lower vehicle completely and remove jack stands
• Start engine and verify no abnormal noises from rear differential
• Test drive vehicle at low speed (under 15 mph) in a safe area and verify smooth operation
• Check for fluid leaks around differential cover and axle seals after initial test drive
• Perform full test drive including acceleration, deceleration, and turns to verify proper operation
• Recheck differential fluid level after test drive and top off if necessary
• Verify no vibration at highway speeds - driveshaft alignment marks should prevent this
• After 50-100 miles, recheck all mounting bolts and wheel lug nuts for proper torque retention

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