This procedure covers removal and replacement of the rear CV axle assembly on a 4WD Ford F-150 with 3.5L EcoBoost engine, including disconnecting the axle from the differential and wheel hub.

Warnings

Tools required

Parts

• Rear CV axle assembly × 1 — Use OEM specification for side being replaced
• Axle hub nut × 1 — One-time use, must replace
• Lower ball joint nut × 1 — Recommended to replace

Fluids

• Motorcraft 75W-140 Synthetic Gear Oil — 0.5 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Chock the front wheels
3. Using a breaker bar and appropriate socket, loosen but do not remove the rear axle hub nut while vehicle is on the ground
4. Loosen the rear wheel lug nuts while vehicle is on the ground
5. Raise the rear of the vehicle and support securely on jack stands at the frame rails
6. Remove the rear wheel on the side being serviced
7. Place a drain pan under the rear differential to catch any fluid spillage

Procedure

1. 1

   Remove axle hub nut
   With the vehicle raised and wheel removed, completely remove the previously loosened axle hub nut. If the nut was staked, use a chisel or punch to straighten the staked portion first. Discard the old nut as it must be replaced.
2. 2

   Disconnect lower ball joint
   Locate the lower control arm ball joint connection at the rear knuckle. Remove the ball joint castle nut. Using a ball joint separator or pickle fork, separate the ball joint from the knuckle. Be careful not to damage the ball joint boot if reusing the control arm.
   ⚠Using a pickle fork will likely damage the ball joint boot. Use a proper ball joint separator if you want to preserve the boot.
3. 3

   Access CV axle differential flange bolts
   Locate the inboard CV joint where it connects to the rear differential output flange. There are typically 6 bolts securing the CV axle flange to the differential flange. Clean the area with a wire brush if necessary to identify all fasteners.
4. 4

   Remove CV axle flange bolts
   Remove all 6 bolts securing the CV axle flange to the differential output flange. You may need to rotate the driveshaft slightly to access all bolts. Support the CV axle to prevent it from dropping suddenly when the last bolt is removed.
   ℹ️Differential fluid may begin draining once the axle is separated from the differential. Have your drain pan positioned appropriately.
5. 5

   Remove CV axle from hub
   Pull the outboard end of the CV axle out of the wheel hub. If the axle is stuck in the hub splines, use a soft-faced hammer to tap the end of the axle shaft while pulling outward. You may need to push the hub/knuckle assembly outward slightly to clear the axle.
6. 6

   Remove CV axle assembly
   Separate the inboard CV joint flange from the differential output flange and carefully remove the entire CV axle assembly from the vehicle. Be prepared for additional gear oil to drain from the differential. Inspect the differential output seal for damage or leakage.
7. 7

   Clean and inspect mounting surfaces
   Clean the differential output flange and the wheel hub splines with a wire brush and clean rag. Inspect the hub splines for damage or excessive wear. Check the differential output seal for any signs of damage or leakage. Replace if necessary.
8. 8

   Install new CV axle into hub
   Align the outboard end of the new CV axle with the wheel hub splines. Push the axle into the hub, ensuring the splines engage properly. The axle should slide in smoothly but may require light tapping with a soft-faced hammer.
9. 9

   Connect CV axle to differential
   Position the inboard CV joint flange to align with the differential output flange. Thread in all 6 flange bolts by hand to ensure proper alignment before tightening. Tighten the bolts in a star pattern to the specified torque.
   Torque spec

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

    Reconnect lower ball joint
    Position the lower control arm ball joint into the knuckle. Install a new ball joint castle nut and tighten to the specified torque. If equipped with a cotter pin, align the castle nut slots and install a new cotter pin.
    Torque spec

    Ball Joint Nut117 Nm (86 lb-ft)
11. 11

    Install and torque axle hub nut
    Install a new axle hub nut onto the axle shaft. Torque the nut to specification using a torque wrench. After torquing, stake the nut collar into the axle shaft groove using a punch and hammer to prevent the nut from loosening.
    ⚠The axle nut must be staked after torquing to prevent it from loosening. Use a blunt punch to deform the nut collar into the shaft groove.
    Torque spec

    Axle Nut281 Nm (207 lb-ft)
12. 12

    Check differential fluid level
    Check the rear differential fluid level through the fill plug. Add Motorcraft 75W-140 Synthetic Gear Oil as needed to bring the level to the bottom of the fill plug hole. Reinstall the fill plug.
13. 13

    Reinstall wheel
    Install the rear wheel and hand-tighten the lug nuts in a star pattern. Lower the vehicle until the tire just touches the ground to prevent wheel rotation. Torque the lug nuts to specification in a star pattern. Fully lower the vehicle and remove jack stands.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to specification
2. Verify the axle hub nut is properly staked
3. Confirm rear differential fluid is at the proper level
4. Double-check that all tools and parts have been removed from under the vehicle

Verification

• Start the engine and verify no unusual noises from the rear axle area
• Test drive the vehicle at low speed and verify smooth operation with no clicking, popping, or vibration
• Check for any fluid leaks around the differential output seal
• Perform a figure-8 turn test in both directions to verify CV joint operation under load
• Re-check all torque specifications after test drive, especially the axle hub nut

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