Ring and Pinion

This procedure covers the removal and replacement of the ring and pinion gears in the front or rear differential of a 2025 Rivian EDV 500 dual motor AWD electric delivery vehicle.

Warnings

Tools required

Parts

• Ring and pinion gear set (front or rear, specify axle) × 1 — Use OEM specification
• Pinion bearing kit (inner and outer bearings with races) × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Pinion nut × 1 — Use OEM specification
• Differential carrier bearings (if reusing, inspect carefully) × 2 — Use OEM specification
• Differential cover gasket or RTV sealant × 1 — Use OEM specification
• Crush sleeve or pinion preload shims × 1 — Use OEM specification
• Ring gear bolts × 10 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect 12V auxiliary battery negative terminal and wait 5 minutes
3. Raise vehicle on lift or support securely on jack stands at manufacturer lift points
4. Remove rear wheels (or front wheels if servicing front differential)
5. Place drain pan under differential
6. Remove differential cover and drain gear oil completely
7. Mark driveshaft and companion flange relationship for installation reference
8. Remove driveshaft and secure out of work area
9. Clean differential cover and housing mating surfaces thoroughly

Procedure

1. 1

   Remove differential carrier assembly
   Mark bearing cap orientation with punch marks. Remove bearing cap bolts and carefully pry bearing caps off. Use two pry bars to gently lift carrier assembly out of housing. Keep carrier bearings with their respective races if reusing.
2. 2

   Measure and record ring gear backlash and runout
   Before disassembly, mount dial indicator against ring gear tooth face. Check backlash at four points 90 degrees apart and record readings. Check ring gear runout at mounting face and record. These measurements will serve as baseline for reassembly.
3. 3

   Remove ring gear from carrier
   Mark ring gear position on carrier for reference. Remove ring gear bolts (they are typically left-hand thread). Use soft mallet to tap ring gear off carrier if necessary. Inspect carrier for cracks or damage.
4. 4

   Remove pinion nut and yoke
   Mark pinion nut position on pinion shaft threads to record pinion bearing preload depth. Use holding tool on companion flange and remove pinion nut. Use puller to remove companion flange/yoke from pinion shaft. Measure and record pinion rotating torque using inch-pound torque wrench before disturbing.
5. 5

   Remove pinion and bearings
   Tap pinion shaft out of housing from front to rear using soft mallet. Catch pinion gear as it exits to prevent dropping. Remove pinion seal from housing using seal puller. Remove outer pinion bearing from housing. Remove crush sleeve or shim pack from pinion shaft. Press inner pinion bearing off pinion shaft. Remove inner and outer bearing races from housing using bearing race puller or brass drift.
6. 6

   Clean and inspect all components
   Thoroughly clean differential housing, carrier, and all bearing surfaces with solvent. Inspect housing for cracks, wear, or damage. Inspect carrier for cracks at bearing bores and ring gear mounting surface. Check all bearing surfaces for pitting, scoring, or wear. Replace any questionable components.
7. 7

   Install new pinion bearing races
   Install new inner and outer pinion bearing races into housing using race driver and press or hammer. Ensure races are fully seated against shoulders in housing. Verify race seating by attempting to insert 0.002 inch feeler gauge between race and shoulder - gauge should not fit.
8. 8

   Determine pinion depth setting
   Install pinion depth setting gauge tools per manufacturer instructions. Use dial indicator to measure pinion depth and compare to new gear set markings (typically etched on pinion head). Calculate required shim thickness based on readings and gear set variance markings. This is critical for proper gear contact pattern.
9. 9

   Assemble pinion with bearings and shims
   Press new inner pinion bearing onto pinion shaft. Install calculated pinion depth shims. Lubricate bearings with gear oil. Install pinion through housing from rear. Install new crush sleeve or outer shim pack. Install outer pinion bearing. Install companion flange and new pinion nut finger tight.
10. 10

    Set pinion bearing preload
    Tighten pinion nut gradually while rotating pinion frequently to seat bearings. Check rotating torque with inch-pound torque wrench after every quarter turn. Target preload is typically 15-25 inch-pounds for new bearings. Do not overtighten - if preload exceeds specification, crush sleeve must be replaced and process restarted. Once correct preload is achieved, install new pinion seal using seal driver.
11. 11

    Install ring gear on carrier
    Clean and inspect ring gear and carrier mounting surfaces. Heat ring gear to 200-250°F if specified for installation. Align ring gear to carrier using alignment marks. Install new ring gear bolts and tighten in star pattern. Apply thread locker per manufacturer specification. Note: verify if bolts are left-hand or right-hand thread for this application.
12. 12

    Install carrier bearings and set carrier preload
    Press new carrier bearings onto carrier if replacing. Install bearing shims as calculated (typically 0.010-0.020 inch preload plus required amount for proper backlash). Place carrier assembly into housing. Install bearing caps in marked positions. Install and tighten bearing cap bolts gradually in cross pattern.
13. 13

    Set ring gear backlash
    Install dial indicator against ring gear tooth face. Check backlash at four points 90 degrees apart. Adjust carrier bearing shims side-to-side to achieve specified backlash (typically 0.005-0.009 inch). Moving shims from one side to other maintains preload while adjusting backlash. Recheck preload after adjustment.
14. 14

    Check gear contact pattern
    Apply thin coat of gear marking compound to 8-10 ring gear teeth. Rotate pinion through mesh under light load (apply resistance to flange). Examine contact pattern on drive and coast sides. Pattern should be centered on tooth face, slightly toward toe. Adjust pinion depth (shims) for lengthwise position and backlash for profile position. Repeat until pattern is acceptable.
15. 15

    Final assembly and fill
    Clean all gear marking compound from gears. Apply new RTV sealant or install new gasket on differential cover. Install cover and tighten bolts in cross pattern. Reinstall driveshaft aligned to marks made during disassembly. Fill differential with 2.0 quarts of 75W-90 GL-5 gear oil (rear) or 1.5 quarts (front). Install fill plug.

Reassembly

1. Reinstall wheels and torque lug nuts to specification
2. Lower vehicle to ground
3. Reconnect 12V auxiliary battery
4. Test drive vehicle at various speeds and listen for abnormal differential noise
5. Recheck differential fluid level after 50-100 miles and top off if necessary

Verification

• Start vehicle and verify no warning lights on instrument cluster
• Test drive vehicle and accelerate moderately - differential should operate quietly with no whining or howling
• Perform figure-8 turns in both directions to load differential under turning conditions
• Check for fluid leaks at pinion seal and differential cover after test drive
• Verify proper operation of AWD system with no vibration or binding
• Recheck gear oil level when cold after test drive - top off if needed

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