Differential Rebuild - Rear

Complete disassembly, inspection, and rebuild of the rear differential assembly including bearing replacement, gear setup, and backlash adjustment for the 2011-2014 Ford F-150 3.5L EcoBoost 4WD.

Warnings

Tools required

Parts

• Rear differential rebuild kit (includes bearings, seals, shims) × 1 — Use OEM specification for axle code
• Pinion crush sleeve × 1 — Use OEM specification
• Pinion nut × 1 — Use OEM specification
• Differential cover gasket or RTV sealant × 1 — Motorcraft TA-31 RTV
• Drain plug washer × 1 — Use OEM specification
• Gear marking compound × 1 — Use OEM specification
• Shop towels × 1 — Generic

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 rear wheels using star pattern to loosen lug nuts
5. Locate and record differential axle code from tag on differential cover for parts ordering
6. Take photos of driveshaft orientation and axle assembly for reference during reassembly
7. Allow differential to cool completely if vehicle was recently operated

Procedure

1. 1

   Drain differential fluid and remove cover
   Place drain pan under differential. If equipped, remove drain plug and allow fluid to drain completely. If no drain plug, loosen all cover bolts gradually to allow fluid to drain. Remove all cover bolts and carefully pry off differential cover. Clean all old RTV sealant from cover and housing mating surfaces using plastic scraper. Inspect drained fluid for metal particles indicating gear damage.
   ⚠Gear oil will drain quickly once cover is loosened. Position drain pan to capture all fluid.
   Torque spec

   Drain Plug47 Nm (35 lb-ft)
2. 2

   Remove driveshaft
   Mark driveshaft flange and pinion flange orientation with paint or marker for proper reassembly alignment. Remove U-joint strap bolts at rear differential. Support driveshaft and slide rearward to separate from pinion flange. Secure driveshaft out of work area or remove completely.
   ⚠Do not allow driveshaft to hang unsupported as this may damage CV joint or transmission output seal.
   Torque spec

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

   Remove axle shafts
   Remove brake calipers and rotors from both sides. Remove axle shaft nuts from both wheel hubs (mark left and right if different specifications). Remove CV bolts connecting inner CV joints to differential stub shafts. Carefully pull axle assemblies outward from differential and support to prevent damage to CV boots.
   ⚠Support axle assemblies to prevent strain on brake lines and ABS sensor wiring.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)

   CV Bolts70 Nm (52 lb-ft)
4. 4

   Remove carrier assembly from housing
   Mark bearing cap orientation and left/right positions with permanent marker. Remove carrier bearing cap bolts. Using case spreader tool, carefully spread carrier housing just enough to remove carrier assembly (do not over-spread). Lift carrier assembly with ring gear attached from housing. Remove and label all shims from carrier bearing bores for reference.
   ⚠️Do not over-spread differential housing beyond tool specifications as this can crack the housing.
5. 5

   Disassemble and inspect carrier
   Remove ring gear bolts from carrier. Using soft mallet, tap ring gear off carrier if tight. Mark differential case halves for reassembly orientation. Remove differential pinion shaft lock bolt and pinion shaft. Remove side gears, pinion gears, and thrust washers, keeping all parts organized. Inspect all gears, carrier, and internal components for wear, scoring, or damage. Replace carrier assembly if cracked or excessively worn.
   ℹ️Take detailed notes or photos of shim locations and thicknesses as these affect gear backlash.
6. 6

   Remove and replace carrier bearings
   Using bearing puller, remove carrier bearings from both sides of carrier assembly. Clean bearing bores thoroughly. Using hydraulic press and bearing installer, press new carrier bearings onto carrier until fully seated. Ensure bearings are installed square and to proper depth.
7. 7

   Remove pinion assembly
   Using pinion holding tool, remove pinion nut (discard old nut). Remove pinion flange using appropriate puller. Carefully tap pinion shaft out from rear of housing, catching pinion gear and components. Remove front pinion bearing, crush sleeve (discard), rear pinion bearing, and pinion seal. Remove pinion bearing races from housing using race puller. Record original shim thickness behind rear pinion bearing for reference.
   ⚠Crush sleeve is one-time use only. Always install new crush sleeve during reassembly.
8. 8

   Clean and inspect all components
   Thoroughly clean differential housing, pinion gear, ring gear, and all internal components using parts cleaner. Inspect ring and pinion gear teeth for pitting, scoring, chipping, or abnormal wear patterns. Inspect housing bearing bores for damage. Check pinion shaft splines for wear. Replace ring and pinion as matched set if any damage is present. Clean and inspect carrier assembly and all internal gears.
   ℹ️Ring and pinion gears are lapped together at factory and must be replaced as matched set.
9. 9

   Install new pinion bearing races and set pinion depth
   Press new front and rear pinion bearing races into housing until fully seated. Install original thickness shim behind rear pinion bearing on pinion shaft. Press rear pinion bearing onto pinion shaft. Measure pinion depth using dial indicator and pinion setting gauge tool. Adjust shim thickness as needed to achieve proper pinion depth per gear set markings (typically etched on pinion head). This is critical for proper gear contact pattern.
   ⚠Pinion depth setting is critical and must be within 0.001 inch of specification. Incorrect depth causes improper gear mesh and premature failure.
10. 10

    Install pinion assembly with proper preload
    Install pinion with correct shim and rear bearing into housing. Install new crush sleeve over pinion shaft. Install front pinion bearing and new pinion seal. Install pinion flange and new pinion nut. Using pinion holding tool and inch-pound torque wrench, gradually tighten pinion nut while checking rotating torque. Tighten until pinion bearing preload reaches 15-25 inch-pounds for new bearings. Do not back off nut - if over-tightened, must replace crush sleeve and restart.
    ⚠️Never back off pinion nut to reduce preload. Crush sleeve will be damaged and pinion nut must be removed, crush sleeve replaced, and process restarted.
    ⚠Tighten pinion nut gradually in small increments while continuously checking preload to avoid over-tightening.
11. 11

    Reassemble carrier assembly
    Install thrust washers, side gears, pinion gears, and pinion shaft into carrier in original orientation. Install pinion shaft lock bolt finger tight. Heat ring gear to approximately 200°F using heat gun or in oven to expand for installation. Quickly align ring gear to carrier in original orientation and install ring gear bolts with thread locker. Torque ring gear bolts to specification in cross pattern. Allow ring gear to cool completely before proceeding.
    ⚠️Use proper heat protective equipment when handling heated ring gear. Ring gear must be heated to expand for proper installation.
12. 12

    Install carrier and set backlash
    Install carrier bearing races onto carrier bearings. Install carrier assembly into housing with original shims as starting point. Install bearing caps in original orientation. Spread housing slightly with case spreader and install carrier. Remove spreader and install cap bolts finger tight. Using dial indicator on ring gear tooth, measure backlash at 4 points around ring gear. Adjust shim thickness (moving shims from one side to other) to achieve 0.004-0.010 inch backlash with 0.006 inch preferred. Tighten bearing cap bolts to specification.
    ⚠Backlash must be consistent around entire ring gear within 0.002 inch variation. Excessive variation indicates bent housing or damaged carrier bearings.
13. 13

    Check gear contact pattern
    Apply thin coat of gear marking compound to 6-8 ring gear teeth in three locations around ring gear. Rotate pinion in both directions under light resistance while maintaining slight pressure on ring gear. Inspect contact pattern on ring gear teeth - pattern should be centered on tooth face for drive and coast sides. If pattern is incorrect, adjust pinion depth shims and/or carrier shims as needed. Repeat until proper pattern is achieved on both drive and coast sides.
    ⚠Gear contact pattern verification is essential. Improper pattern will cause noise, vibration, and premature gear failure.
14. 14

    Final assembly and fill
    Torque differential pinion shaft lock bolt to specification. Clean all RTV sealant from cover and housing mating surfaces. Apply continuous 1/4 inch bead of RTV sealant to differential cover. Install cover and torque cover bolts in cross pattern to specification. Allow RTV to cure per manufacturer instructions (typically 1 hour before filling, 24 hours before operation). Install and torque fill plug. Remove fill plug and add Motorcraft 75W-140 Synthetic Gear Oil until level reaches bottom of fill plug hole (approximately 2.0-2.5 quarts). Install and torque fill plug with new washer.
    ℹ️Allow RTV sealant to cure fully before test driving vehicle to prevent leaks.
    Torque spec

    Cover Bolts39 Nm (29 lb-ft)

    Fill Plug47 Nm (35 lb-ft)
15. 15

    Reinstall driveshaft and axles
    Install axle shafts into differential, ensuring proper engagement with stub shafts. Install and torque CV bolts to specification. Install axle nuts and torque to specification, then install new cotter pins or stake nuts as applicable. Align driveshaft to pinion flange using alignment marks made during disassembly. Install U-joint strap bolts and torque evenly in cross pattern to specification. Install brake rotors and calipers. Install wheels and torque lug nuts in star pattern to specification.
    Torque spec

    CV Bolts70 Nm (52 lb-ft)

    Axle Nut250 Nm (184 lb-ft)

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

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Double-check all fastener torque values with torque wrench, especially pinion nut and carrier cap bolts
2. Verify differential fluid is at proper level at fill plug hole
3. Ensure all brake components are properly reinstalled and bled if brake lines were disconnected
4. Verify driveshaft alignment marks match original orientation
5. Check for any fluid leaks around cover, pinion seal, and axle seals before lowering vehicle

Verification

• Lower vehicle and torque wheel lug nuts to final specification in star pattern
• Test drive vehicle and verify no abnormal noises, vibrations, or whining from differential
• Check for proper operation through full range of speeds and under light and heavy acceleration
• After 50-100 miles, recheck differential fluid level and inspect for leaks at cover, pinion seal, and axle seals
• Listen for any whining, howling, or clunking noises which would indicate improper gear setup
• After 500 miles, consider changing differential fluid to remove any break-in debris from new bearings and gears

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