This procedure covers the replacement of the differential pinion seal on a 2025 Rivian EDV 500 dual motor AWD system, requiring removal of the driveshaft and pinion flange to access and replace the seal.

Warnings

Tools required

Parts

• Differential pinion seal × 1 — Use OEM Rivian specification
• Pinion nut (if not reusable) × 1 — Use OEM Rivian specification
• Driveshaft fasteners (if required) × 1 — Use OEM specification
• Differential cover gasket or RTV sealant × 1 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Place vehicle in service mode per Rivian service procedures to disable high-voltage systems
2. Disconnect the 12V battery negative terminal and wait 5 minutes
3. Raise vehicle on lift or support securely on jack stands at manufacturer-specified lift points
4. Remove rear wheels if servicing rear differential, or front wheels if servicing front differential
5. Place wheel chocks on opposite axle wheels
6. Verify differential to be serviced (front: 1.5 qt capacity, rear: 2.0 qt capacity)
7. Clean area around differential thoroughly to prevent contamination during service

Procedure

1. 1

   Drain differential fluid
   Position drain pan beneath differential. Remove the differential drain plug using appropriate socket. Allow all gear oil to drain completely (approximately 10-15 minutes). Inspect drained fluid for metal particles or contamination that may indicate bearing or gear damage. If excessive contamination is present, further differential inspection is required.
2. 2

   Mark driveshaft alignment
   Using marking paint or a center punch, create alignment marks on the driveshaft flange and the pinion flange. These marks must align during reassembly to maintain driveshaft balance and prevent vibration. Mark both sides of the flange connection and take a photo for reference.
3. 3

   Remove driveshaft from pinion flange
   Remove the fasteners connecting the driveshaft to the differential pinion flange. Support the driveshaft with a strap or have an assistant hold it to prevent damage. Lower or move the driveshaft clear of the work area, taking care not to overextend CV joints or U-joints. Secure driveshaft to prevent it from hanging on the remaining connection point.
4. 4

   Mark pinion flange position and count rotational preload
   Mark the pinion flange position relative to the pinion shaft using paint to ensure proper reassembly depth. Using an inch-pound torque wrench on the pinion nut, measure and record the rotational torque required to turn the pinion (this is the bearing preload). Typical reading should be 15-25 inch-pounds. This value must be matched or slightly exceeded during reassembly.
   ⚠Accurate preload measurement is critical. If preload cannot be measured or is outside normal range, differential may require complete rebuild with new bearings.
5. 5

   Remove pinion nut
   Using the pinion flange holding tool to prevent rotation, remove the pinion nut with appropriate socket. An impact wrench may be used if a holding tool is securely in place. Note the condition of the pinion nut threads - if deformed or damaged, the nut must be replaced. Remove and retain any washers or spacers present.
6. 6

   Remove pinion flange
   Using a suitable puller or by carefully tapping with a soft mallet while prying with a pry bar, remove the pinion flange from the pinion shaft. The flange should slide off with moderate force. Do not allow the pinion shaft to fall inward into the differential housing. If shaft moves inward, pinion bearing preload will be lost and complete differential setup will be required.
   ⚠️Do not allow pinion shaft to drop into differential housing. Have an assistant support the pinion or use a puller that prevents inward movement.
7. 7

   Remove old pinion seal
   Using a seal puller or pick tool, carefully remove the old pinion seal from the differential housing. Work around the seal circumference to pry it out evenly. Avoid damaging the seal bore surface in the housing. Inspect the seal bore for scratches, grooves, or damage that could cause the new seal to leak.
8. 8

   Inspect pinion shaft and flange
   Thoroughly clean and inspect the pinion shaft sealing surface and the pinion flange. Look for grooves, pitting, or wear in the seal contact area. Minor imperfections can be polished with fine emery cloth, but deep grooves require shaft or flange replacement. Check pinion shaft splines for damage. Inspect the flange bore for cracks.
9. 9

   Install new pinion seal
   Lightly coat the outer diameter of the new seal with gear oil. Apply a thin film of gear oil to the seal lip. Using a seal driver of appropriate size (or large socket that contacts only the outer seal edge), carefully drive the new seal into the housing bore. Tap evenly around the circumference until the seal is fully seated and flush with the housing face. Verify the seal is not cocked or damaged.
   ⚠Never strike the seal face directly. Contact only the outer metal edge to prevent seal distortion.
10. 10

    Reinstall pinion flange
    Lightly coat the pinion shaft sealing surface with clean gear oil. Align the pinion flange with the shaft splines and your alignment marks from Step 4. Slide the flange onto the shaft, ensuring it seats to the same depth as marked. Install any washers or spacers that were removed. Thread the pinion nut onto the shaft by hand.
11. 11

    Torque pinion nut to achieve proper preload
    Using the flange holding tool and torque wrench, tighten the pinion nut in stages. After each stage, check rotational torque with an inch-pound torque wrench. Continue tightening until the rotational preload equals or slightly exceeds (by 5 inch-pounds maximum) the value recorded in Step 4. Do not overtighten. If preload specification is exceeded, the pinion nut must be removed and the procedure restarted with a new collapsible spacer if equipped.
    ⚠️Do not overtighten pinion nut. Excessive preload will cause immediate bearing failure. If target preload is exceeded, do not loosen nut - complete disassembly and new components are required.
12. 12

    Reinstall driveshaft
    Position the driveshaft to the pinion flange, carefully aligning the marks created in Step 2. Install all driveshaft fasteners and tighten in a star pattern to prevent flange distortion. Use new fasteners if originals show thread damage or stretching. Without factory torque specifications, tighten securely and verify all fasteners are tight after initial test operation.
13. 13

    Refill differential with gear oil
    Using a fluid pump, refill the differential through the fill hole with the appropriate quantity of 75W-90 GL-5 gear oil (1.5 quarts for front differential, 2.0 quarts for rear differential). Fill until oil reaches the bottom of the fill hole and begins to drip out. Install and tighten the fill plug. Wipe all surfaces clean.
14. 14

    Check for leaks and verify installation
    With vehicle still raised, inspect the pinion seal area carefully for any signs of leakage. Rotate the driveshaft by hand to verify smooth operation with no binding or unusual noise. Check that all fasteners are tight. Reinstall wheels if removed.

Reassembly

1. Reinstall wheels and torque lug nuts to manufacturer specification
2. Lower vehicle to ground
3. Reconnect 12V battery negative terminal
4. Exit service mode per Rivian procedures
5. Torque wheel lug nuts again after vehicle is on ground with full weight

Verification

• Test drive vehicle at various speeds to verify no vibration or driveline noise
• After initial test drive (10-15 miles), re-inspect pinion seal area for any signs of leakage
• Check differential oil level again after test drive - top off if necessary
• Verify no unusual noises from differential under acceleration and deceleration
• Re-inspect all driveshaft fasteners for tightness after 50 miles of operation

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