Differential Fluid Change - Rear

This procedure covers draining and refilling the rear differential fluid on the 2023 Rivian EDV 500 electric delivery vehicle with dual motor AWD configuration.

Warnings

Tools required

Parts

• Rear differential drain plug washer/gasket × 1 — Use OEM specification
• Rear differential fill plug o-ring × 1 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Place wheel chocks at front wheels
3. Put vehicle into service mode following manufacturer's high-voltage safety procedures
4. Allow differential to cool if vehicle was recently operated
5. Raise vehicle on lift or safely support on jack stands at manufacturer-specified lift points
6. Remove rear wheels to improve access to differential housing
7. Clean area around differential drain and fill plugs with degreaser and wire brush

Procedure

1. 1

   Locate differential service plugs
   Identify the rear differential fill plug (upper position on differential housing) and drain plug (lower position). The fill plug must be loosened BEFORE draining to ensure you can refill the differential after draining.
2. 2

   Break loose fill plug first
   Using appropriate socket, carefully loosen the fill plug 2-3 turns but do not remove completely. This ensures the plug is not seized before draining fluid. If fill plug cannot be loosened, do not proceed with drain - seek assistance or apply penetrating oil and wait.
3. 3

   Position drain pan
   Place drain pan with at least 3 quart capacity directly under the differential drain plug. Position pan slightly forward as fluid will initially stream outward before dropping straight down.
4. 4

   Remove drain plug and drain fluid
   Remove the drain plug completely and allow fluid to drain fully into pan. This may take 10-15 minutes for complete drainage. Inspect drained fluid for metal particles, contamination, or unusual odor which may indicate internal damage.
   ⚠Gear oil may still be warm. Wear gloves to avoid skin contact with used gear oil.
5. 5

   Inspect and clean drain plug
   Inspect drain plug threads and magnetic tip (if equipped) for metal shavings or debris. Small amounts of fine metallic dust are normal, but large particles or chunks indicate abnormal wear. Clean plug thoroughly with shop rag. Inspect drain plug sealing washer/gasket for damage.
6. 6

   Install new drain plug washer
   Remove old sealing washer from drain plug and install new OEM washer/gasket. Ensure washer seats properly on plug shoulder.
7. 7

   Reinstall drain plug
   Thread drain plug in by hand to avoid cross-threading. Tighten drain plug to manufacturer specification using torque wrench. Without specific torque value in database, use conservative approach: snug plus 1/4 turn, ensuring washer is compressed but plug housing is not over-stressed.
   ⚠Over-tightening drain plug can strip aluminum differential housing threads. Use calibrated torque wrench when specification is available.
8. 8

   Remove fill plug completely
   Remove the fill plug completely along with its o-ring. Inspect o-ring for cuts, compression set, or damage. Replace with new OEM o-ring.
9. 9

   Fill differential with gear oil
   Using fluid transfer pump or squeeze bottle, add 75W-90 GL-5 gear oil through fill hole. Fill until oil begins to drip out of fill hole opening. The differential requires approximately 2.0 quarts. Fill slowly to allow air to escape and prevent overfilling.
   ℹ️Oil level is correct when it just begins to seep from the fill hole with vehicle level. Do not overfill.
10. 10

    Install fill plug with new o-ring
    Ensure new o-ring is properly seated in fill plug groove. Thread fill plug in by hand, then tighten to manufacturer specification using torque wrench. Without specific torque value, tighten until o-ring is just compressed and plug is snug.
11. 11

    Clean differential housing
    Wipe down differential housing and surrounding area to remove any spilled gear oil. Check both drain and fill plugs for signs of leakage.
12. 12

    Reinstall rear wheels
    Reinstall rear wheels and torque lug nuts to manufacturer specification in proper star pattern sequence.

Reassembly

1. Lower vehicle to ground
2. Remove wheel chocks
3. Exit service mode and restore vehicle to normal operation per manufacturer procedures
4. Dispose of used gear oil properly at recycling facility - do not pour down drain or discard in trash

Verification

• Start vehicle and allow rear motor to operate briefly (accelerate gently in safe area)
• Re-check fill plug for leaks after initial operation
• After 50-100 miles of driving, re-inspect both drain and fill plugs for signs of seepage
• Check differential fluid level again after first drive cycle - top off if needed
• Record service date and mileage in vehicle maintenance log

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