Ring and Pinion

This procedure covers the removal and replacement of the rear differential ring and pinion gears on a 2015-2020 Ford F-150 with 3.5L EcoBoost engine and RWD configuration.

Warnings

Tools required

Parts

• Ring and pinion gear set with correct ratio × 1 — Use OEM specification for desired gear ratio
• Pinion bearing kit (inner and outer bearings with races) × 1 — Use OEM specification
• Carrier bearing kit × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Differential cover gasket × 1 — Use OEM specification
• Crush sleeve (pinion preload) × 1 — Use OEM specification
• Ring gear bolts × 10 — Use OEM specification
• Gear marking compound × 1 — Generic
• RTV silicone sealant (differential grade) × 1 — Motorcraft TA-357

Fluids

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

Preparation

1. Park vehicle on level surface and engage parking brake
2. Loosen rear wheel lug nuts while vehicle is on ground
3. Raise vehicle and support securely on jack stands at frame contact points
4. Remove rear wheels
5. Place drain pan under differential
6. Mark driveshaft and pinion flange orientation for reinstallation alignment
7. Have all replacement parts, shims, and bearings ready before disassembly

Procedure

1. 1

   Remove driveshaft and drain differential
   Remove the four U-joint strap bolts securing the driveshaft to the pinion flange. Support the driveshaft and slide it rearward to separate from the pinion flange. Secure driveshaft out of the way. Remove the differential cover bolts and carefully pry cover loose. Allow gear oil to drain completely into drain pan.
   Torque spec

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

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

   Remove axle shafts
   Remove the brake calipers and rotors. Remove the axle shaft retaining bolts from inside the differential housing. Carefully withdraw both axle shafts from the housing, being careful not to damage the axle seals. Set axle shafts aside in a clean area.
3. 3

   Mark and measure carrier bearing caps
   Mark the carrier bearing caps and housing with alignment marks for reassembly orientation. Using a dial indicator, measure and record ring gear backlash at four points around the ring gear (90-degree intervals). Measure and record carrier bearing preload if possible. Remove carrier bearing cap bolts.
   Torque spec

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

   Remove carrier assembly
   Carefully pry carrier assembly with ring gear from the housing. If equipped with axle spreader tool, use it to slightly spread housing (maximum 0.015 inches). Otherwise, use light prying pressure alternating sides. Remove carrier assembly and place on clean workbench. Remove carrier bearing caps and mark shim positions and thicknesses for reference.
5. 5

   Remove pinion assembly
   Mark pinion nut position and depth for reference. Using pinion holding tool to prevent rotation, remove pinion nut. Use puller to remove pinion flange. Carefully tap pinion shaft rearward out of housing, catching pinion and inner bearing. Remove pinion seal, outer bearing, and bearing races from housing. Remove crush sleeve from pinion shaft and discard.
6. 6

   Disassemble carrier and remove old ring gear
   Press or drive carrier bearings off carrier. Mark old ring gear bolt loosening sequence. Heat ring gear bolts if necessary and remove using proper left-hand thread procedure (if applicable - verify bolt thread direction). Separate ring gear from carrier. Clean all components thoroughly with solvent and inspect for wear or damage.
7. 7

   Install new bearings and races
   Using hydraulic press and proper drivers, install new pinion bearing races into housing, ensuring they seat completely. Press new carrier bearings onto carrier assembly. Press inner pinion bearing onto pinion shaft. Ensure all bearings are seated properly and races are flush in housing.
8. 8

   Install new ring gear on carrier
   Clean ring gear and carrier mating surfaces thoroughly. Align ring gear on carrier, ensuring proper orientation. Install new ring gear bolts and tighten in star pattern. Follow manufacturer specified torque sequence, typically requiring torque in multiple stages to final specification.
9. 9

   Set pinion depth and install pinion
   Determine correct pinion depth shim thickness based on pinion depth variance number marked on pinion gear and old shim measurements. Install selected shim on pinion shaft. Install inner bearing, new crush sleeve, and carefully insert pinion into housing. Install outer bearing, pinion flange, and new pinion nut.
10. 10

    Set pinion bearing preload
    Using pinion holding tool and torque wrench, tighten pinion nut gradually while rotating pinion frequently to seat bearings. Check rotating torque with inch-pound torque wrench. Target preload is typically 16-29 in-lbs for new bearings. Tighten pinion nut in small increments until proper preload is achieved. Do not back off nut - if exceeded, replace crush sleeve and start over.
11. 11

    Install carrier assembly with shims
    Install carrier bearing shims from reference measurements. Place carrier assembly into housing, ensuring proper orientation per alignment marks. Install carrier bearing caps in correct positions per marks. Install cap bolts finger tight.
12. 12

    Set ring gear backlash
    Tighten carrier bearing cap bolts to specification. Mount dial indicator to housing with plunger against ring gear tooth. Check backlash at four points around ring gear while holding pinion stationary. Target backlash is typically 0.005-0.009 inches. Adjust by moving shims from one side to other (same total thickness). Thicker shim on ring gear side decreases backlash.
    Torque spec

    Mounting Bolts31 Nm (23 lb-ft)
13. 13

    Check gear tooth contact pattern
    Apply gear marking compound to several ring gear teeth. Rotate pinion through several revolutions in both directions under light load. Examine contact pattern on drive and coast sides. Pattern should be centered on tooth face. Adjust pinion depth shims if pattern is too high or low. Adjust backlash if pattern is too far toward toe or heel. Repeat until proper pattern is achieved.
14. 14

    Install axle shafts and differential cover
    Install new pinion seal using seal driver. Clean differential cover and housing mating surfaces thoroughly. Apply new gasket or RTV sealant per manufacturer specification. Install axle shafts into housing, ensuring they engage differential side gears properly. Install axle retaining bolts. Install differential cover and torque bolts in crisscross pattern.
    Torque spec

    Differential Cover Bolts35 Nm (26 lb-ft)
15. 15

    Fill differential and install driveshaft
    Fill differential with Motorcraft 75W-140 Synthetic Gear Oil to proper level (approximately 2.0-2.5 quarts until level with fill hole). Install fill plug. Align driveshaft to pinion flange per alignment marks made during disassembly. Install U-joint strap bolts and torque evenly. Install wheels and torque lug nuts in star pattern.
    Torque spec

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

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all fasteners are torqued to specification in proper sequence
2. Verify axle shafts are fully engaged and secured
3. Double-check differential fluid level at fill plug
4. Verify driveshaft alignment marks are properly matched

Verification

• Lower vehicle and test drive at low speed, listening for abnormal gear noise or vibration
• Check for leaks around pinion seal and differential cover after test drive
• Verify smooth operation with no whining, clunking, or grinding noises
• Recheck differential fluid level after test drive and top off if necessary
• Monitor differential temperature - excessive heat indicates incorrect setup
• After 500 miles, recheck differential fluid level and inspect for metal particles indicating gear wear

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