This procedure replaces the limited slip clutch pack in the rear differential of a 2011-2014 Ford F-150 3.5L EcoBoost 4WD, requiring differential removal, disassembly, clutch pack replacement, and refill.

Warnings

Tools required

Parts

• Limited slip clutch pack kit × 1 — Use OEM Ford specification for 9.75-inch rear axle
• Differential cover gasket × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Axle seals × 2 — Use OEM specification
• Crush sleeve (if applicable) × 1 — Use OEM specification
• Differential bearing shims (assorted) × 1 — Use OEM specification
• RTV silicone gasket maker × 1 — Motorcraft TA-31 or equivalent
• Thread locker (medium strength) × 1 — Blue Loctite 242 or equivalent

Fluids

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

Preparation

1. Park vehicle on level surface and engage parking brake
2. Chock front wheels securely
3. Raise rear of vehicle and support on jack stands at frame rails
4. Remove both rear wheels
5. Place drain pan under rear differential
6. Allow differential to cool completely if recently driven

Procedure

1. 1

   Remove differential cover and drain fluid
   Loosen all differential cover bolts in a crisscross pattern, leaving top bolts finger-tight. Carefully pry cover loose at bottom to allow fluid to drain into pan. Once drained, remove remaining bolts and cover. Remove and discard gasket. Clean mating surfaces thoroughly with brake cleaner and scraper.
   Torque spec

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

   Disconnect driveshaft
   Mark relationship between driveshaft yoke and pinion flange for reassembly. Remove the four U-joint strap bolts at the rear differential. Secure driveshaft to frame with wire or strap to prevent damage to center bearing.
   ℹ️Mark driveshaft orientation to prevent vibration during reassembly.
   Torque spec

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

   Remove axle shafts
   If equipped with rear disc brakes, remove brake caliper mounting bolts and secure calipers with wire. Remove brake rotors. Remove axle shaft retaining bolts from backing plate. Using a slide hammer with axle puller attachment, extract both axle shafts from differential housing. Inspect axle seals and bearings.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
4. 4

   Mark and measure pinion bearing preload
   Using an inch-pound torque wrench on the pinion nut, measure and record the rotational torque required to turn the pinion (pinion bearing preload). This is critical for reassembly. Mark the pinion nut position relative to pinion shaft threads with paint or marker. This establishes your baseline pinion depth.
   ⚠Accurate preload measurement is critical. Typical preload is 15-25 inch-pounds for used bearings. Record this value.
5. 5

   Remove differential carrier assembly
   Remove carrier bearing cap bolts (typically 4 bolts). Mark bearing caps and their orientation with a center punch or marker. Using pry bars on both sides, carefully work the carrier assembly out of the housing. Place carrier assembly on a clean workbench. Note the position and thickness of any shims behind carrier bearings.
   ℹ️Keep all shims organized by side and position. These determine carrier bearing preload and must be reinstalled correctly.
6. 6

   Disassemble differential carrier
   Remove ring gear bolts using proper impact or socket tools (ring gear bolts are typically left-hand thread). Using a case spreader tool, carefully spread the carrier case just enough to remove the cross shaft retaining pin. Remove cross shaft pin, then slide out the differential cross shaft (spider gear shaft). Remove spider gears and side gears, keeping them in order. Remove the limited slip clutch pack assembly, noting the exact order and orientation of friction discs and steel plates.
   ⚠Do not over-spread the carrier case. Maximum spread is typically 0.015 inches or case damage will occur.
   ℹ️Photograph clutch pack arrangement before removal to ensure correct reassembly sequence.
7. 7

   Inspect components and install new clutch pack
   Clean all components with brake cleaner. Inspect spider gears, side gears, and cross shaft for wear or damage. Check case for cracks. Install new limited slip clutch pack according to manufacturer instructions, alternating friction discs and steel plates in the correct sequence. Soak friction discs in 75W-140 gear oil for at least 30 minutes before installation. Install side gears with clutch packs.
   ℹ️Clutch pack sequence is critical. Typically alternates friction disc (splined to case) with steel plate (splined to side gear). Verify with kit instructions.
8. 8

   Reassemble differential carrier
   Install spider gears and cross shaft through case and gears. Align cross shaft retaining pin hole. Use case spreader to spread case slightly, then install cross shaft pin. Remove spreader. Apply thread locker to ring gear bolts and install ring gear to case. Torque ring gear bolts to specification (typically 100-120 ft-lbs in crisscross pattern). Verify ring gear runout with dial indicator (maximum 0.005 inches).
   ℹ️Ring gear bolts are often left-hand thread. Turn counterclockwise to tighten.
9. 9

   Install carrier assembly and set bearing preload
   Install carrier assembly into housing with original shims. Install bearing caps in their original positions (note match marks). Tighten bearing cap bolts to specification. Check ring gear backlash with dial indicator at multiple points around ring gear (specification typically 0.005-0.009 inches). Adjust shims as needed to achieve proper backlash and bearing preload. Add shims to one side and remove equal amount from opposite side to adjust backlash without changing preload.
   ⚠Carrier bearing preload and ring gear backlash must be set correctly or differential will fail. This requires experience and precision measurement.
10. 10

    Check gear pattern
    Apply gear marking compound to several ring gear teeth. Rotate pinion through several revolutions in both directions while applying light resistance. Examine tooth contact pattern on ring gear. Pattern should be centered on tooth face. Adjust pinion depth (shims) and backlash (carrier shims) as needed to achieve proper pattern.
    ℹ️Proper gear pattern is essential for quiet operation and longevity. Drive side pattern should cover 50-60% of tooth length, centered on tooth height.
11. 11

    Install new axle seals and axle shafts
    Using seal driver, install new axle seals into housing. Apply thin coat of gear oil to seal lips. Carefully insert axle shafts into housing, ensuring splines engage with differential side gears. Install axle shaft retaining bolts and torque to specification.
    Torque spec

    Mounting Bolts31 Nm (23 lb-ft)
12. 12

    Install differential cover and refill
    Clean differential cover and housing mating surfaces thoroughly. Install new gasket or apply 1/8-inch bead of RTV silicone to cover. Install cover and bolts, tightening in crisscross pattern. Fill differential with Motorcraft 75W-140 synthetic gear oil until level reaches fill hole (approximately 2.5 quarts for rear differential with limited slip). Install fill plug.
    ℹ️If using RTV instead of gasket, allow 30 minutes cure time before filling with oil.
    Torque spec

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

    Reconnect driveshaft
    Align driveshaft yoke to pinion flange using alignment marks made during disassembly. Install U-joint strap bolts and tighten evenly in crisscross pattern to specified torque. Ensure straps seat properly on bearing caps.
    ⚠U-joint straps are brittle and can crack if over-torqued. Use exact torque specification.
    Torque spec

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

    Reinstall wheels and lower vehicle
    If removed, reinstall brake rotors and calipers. Install rear wheels and hand-tighten lug nuts. Lower vehicle to ground. Torque lug nuts to specification in star pattern.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all bearing caps and components are installed in their original positions with match marks aligned
2. Verify differential cover is sealed properly with no leaks after initial test drive
3. If using RTV silicone, ensure adequate cure time before operating vehicle
4. Double-check all torque specifications, especially wheel lug nuts and driveshaft straps

Verification

• Start engine and shift through all gears to verify proper clutch pack operation
• Test drive vehicle at varying speeds, confirming smooth operation and no unusual noises from differential
• Perform figure-eight turns in both directions to verify limited slip engagement
• Check for leaks around differential cover and axle seals after test drive
• Re-check differential fluid level after test drive and top off if necessary
• Listen for whine or growl under load which would indicate improper gear pattern or bearing preload
• Verify both rear wheels receive power when one is lifted off ground (limited slip function test)

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