Replace the differential pinion seal on a 2022 Rivian EDV 500 to stop leaks at the pinion shaft. This procedure involves removing the driveshaft, pinion flange, and installing a new seal.

Warnings

Tools required

Parts

• Differential pinion seal × 1 — Use OEM Rivian specification
• Pinion nut (replace if damaged or per OEM spec) × 1 — Use OEM Rivian specification
• Driveshaft flange bolts (if reuse not allowed) × 4 — Use OEM Rivian specification
• RTV silicone sealant × 1 — High-temp differential grade

Fluids

• 75W-90 GL-5 Gear Oil (front or rear differential) — 2 qt

Preparation

1. Verify which differential (front or rear) requires pinion seal replacement by inspecting for oil leaks at the pinion flange area
2. Ensure vehicle battery is at low state of charge or follow Rivian service procedures for disabling high voltage system if working near drive units
3. Raise vehicle on lift or jack stands at designated lift points and ensure stability
4. Remove appropriate wheels to access differential if necessary for clearance
5. Clean exterior of differential housing and driveshaft connection area to prevent contamination during service
6. Place drain pan under differential

Procedure

1. 1

   Mark and remove driveshaft
   Using paint marker or chalk, mark the relationship between the driveshaft flange and the pinion flange for proper alignment during reassembly. Remove the driveshaft flange bolts and carefully separate the driveshaft from the differential pinion flange. Support the driveshaft and secure it out of the way using mechanics wire or by removing it completely if necessary for access.
2. 2

   Drain differential fluid
   Locate and remove the differential drain plug, allowing gear oil to drain completely into the drain pan. If the differential does not have a drain plug, fluid will drain when the pinion seal is removed. Note the condition and quantity of fluid drained for comparison with specification.
3. 3

   Measure and record pinion bearing preload
   Before loosening the pinion nut, use an inch-pound torque wrench to measure the rotating torque required to turn the pinion (pinion bearing preload). Rotate the pinion several times to seat bearings, then measure the torque needed to maintain constant rotation. Record this value as it must be matched or slightly exceeded during reassembly. Typical preload is 15-30 inch-pounds for used bearings, but record the actual measured value.
4. 4

   Mark pinion position and remove pinion nut
   Mark the position of the pinion flange on the pinion shaft using paint marker for reference. Install the pinion flange holding tool to prevent rotation. Using a breaker bar and appropriate socket, remove the pinion nut. This nut is typically very tight (200+ ft-lbs). Note the depth of the pinion flange on the shaft or count exposed threads for reassembly reference.
5. 5

   Remove pinion flange
   Remove the pinion flange holding tool. Using a flange puller or by carefully tapping with a soft mallet, remove the pinion flange from the pinion shaft. Note the orientation and position of any washers or spacers behind the flange. Some fluid may leak out at this point.
6. 6

   Remove old pinion seal
   Using a seal puller or carefully positioned pry bar, extract the old pinion seal from the differential housing. Work carefully to avoid damaging the seal bore in the housing. Inspect the seal bore for gouges, scratches, or damage that could cause the new seal to leak.
7. 7

   Inspect pinion shaft and components
   Carefully inspect the pinion shaft sealing surface (where the seal rides) for grooves, pitting, or damage. Minor imperfections can be smoothed with fine emery cloth, but significant damage requires pinion replacement. Inspect the pinion flange for wear or damage. Check that the slinger (if equipped) behind the seal is in good condition.
8. 8

   Install new pinion seal
   Lightly coat the outer diameter of the new pinion seal with RTV silicone or differential fluid. Coat the seal lip with clean gear oil. Using a seal driver or appropriately sized socket that contacts only the outer edge of the seal, carefully drive the new seal squarely into the bore until it is seated at the same depth as the original seal. Ensure the seal is not cocked or damaged during installation.
9. 9

   Reinstall pinion flange
   Apply a light coat of gear oil to the pinion shaft and seal lip. Reinstall any spacers or washers in their original positions. Carefully slide the pinion flange onto the pinion shaft, aligning with the reference marks made earlier. Ensure the flange does not damage the new seal lip during installation.
10. 10

    Install and torque pinion nut to achieve proper preload
    Install a new pinion nut (or reuse if allowed per manufacturer specification). Install the flange holding tool. Gradually tighten the pinion nut, checking pinion bearing preload frequently with the inch-pound torque wrench as you approach the original preload value. The new preload should equal or slightly exceed (by 5 inch-pounds) the original recorded preload, but do not exceed maximum specification. Once correct preload is achieved, verify the pinion flange alignment marks match. If alignment is significantly off, disassembly and inspection of components may be required.
11. 11

    Verify pinion bearing preload
    Remove the flange holding tool. Rotate the pinion several complete revolutions by hand to seat all components. Recheck the rotating torque with the inch-pound torque wrench to verify preload is within specification. The pinion should rotate smoothly without binding or roughness. If preload is not correct, the pinion nut must be adjusted.
12. 12

    Refill differential with gear oil
    Reinstall the drain plug if removed. Using a fluid pump or funnel with hose, refill the differential with the appropriate quantity of 75W-90 GL-5 gear oil through the fill port. For front differential use 1.5 quarts, for rear differential use 2.0 quarts. Fill until fluid reaches the bottom of the fill hole or per manufacturer specification. Reinstall fill plug.
13. 13

    Reinstall driveshaft
    Position the driveshaft to the pinion flange, aligning the reference marks made during disassembly. Install the driveshaft flange bolts and tighten in a cross pattern. Apply thread locker if specified by manufacturer. Verify all bolts are properly seated and torqued.

Reassembly

1. Reinstall wheels if removed and torque lug nuts to specification
2. Lower vehicle to ground
3. Wipe down all components and inspect for any fluid leaks around the new pinion seal
4. Dispose of used gear oil according to local environmental regulations

Verification

• Start vehicle and operate in a safe area, allowing both forward and reverse movement to distribute gear oil throughout differential
• Test drive vehicle at various speeds and monitor for unusual noises from differential area
• After test drive, re-inspect pinion seal area for any signs of leakage with vehicle on lift
• Recheck differential fluid level after initial operation and top off if necessary
• Monitor seal area for leaks over the next several days of operation
• Verify no vibration or driveline issues are present that could indicate improper driveshaft installation

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