Reduction Gear Service

This procedure covers the removal, inspection, and reinstallation of the reduction gears in the front and/or rear drive units of the 2022 Rivian EDV 500 electric delivery van.

Warnings

Tools required

Parts

• Drive unit reduction gear assembly × 1 — Use OEM specification
• Drive unit drain plug washer × 2 — Use OEM specification
• Drive unit fill plug O-ring × 2 — Use OEM specification
• Output shaft seal × 2 — Use OEM specification
• Drive unit mounting bolts × 1 — Use OEM specification if reuse not permitted
• Halfshaft retaining clips × 2 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil (front) — 1.5 qt
• 75W-90 GL-5 Gear Oil (rear) — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks at all four wheels
3. Disconnect 12V auxiliary battery negative terminal
4. Access high-voltage service disconnect panel behind driver seat
5. Remove high-voltage service disconnect and store in lockable location
6. Wait minimum 5 minutes for high-voltage capacitors to discharge
7. Verify zero voltage at high-voltage terminals using insulated multimeter
8. Apply high-voltage lockout/tagout procedure per facility safety protocols
9. Raise vehicle on lift to full working height
10. Remove all four wheels and set aside

Procedure

1. 1

   Drain drive unit gear oil
   Position drain pan under front drive unit. Remove the drain plug from the bottom of the front drive unit housing and allow gear oil to completely drain (approximately 1.5 quarts). Inspect drained oil for metal particles or contamination. Repeat process for rear drive unit (approximately 2.0 quarts). Replace drain plug washers during reinstallation.
2. 2

   Disconnect halfshafts from drive units
   Remove the halfshaft retaining bolts at the drive unit output flanges on both sides. Carefully pull halfshafts outward and support with mechanics wire to prevent joint damage. Do not allow halfshafts to hang freely. Mark left and right sides for proper reinstallation.
3. 3

   Disconnect electrical connectors
   Locate and disconnect all electrical connectors from the drive unit being serviced, including motor resolver/encoder connectors, temperature sensors, and any ground straps. Label each connector with tape for identification during reassembly. Secure connectors away from work area.
4. 4

   Disconnect coolant lines
   Place drain pan under drive unit coolant connections. Carefully disconnect the inlet and outlet coolant lines from the drive unit motor housing. Have shop towels ready to catch residual coolant (approximately 1 quart per drive unit). Cap or plug open coolant lines to prevent contamination.
5. 5

   Remove drive unit mounting hardware
   Position drive unit support fixture or transmission jack under the drive unit housing. Support the weight of the unit before removing mounting bolts. Remove all drive unit mounting bolts connecting the unit to the subframe and suspension cradle. Count and organize bolts by location as bolt lengths may vary.
6. 6

   Lower and remove drive unit
   Carefully lower the drive unit on the support fixture while guiding it clear of the vehicle chassis and coolant lines. Ensure nothing is binding or catching during removal. Once clear, transfer drive unit to a clean workbench. Repeat process for second drive unit if servicing both.
7. 7

   Disassemble drive unit housing
   With drive unit on workbench, remove the gear case cover bolts in a cross pattern to prevent warping. Carefully separate the gear case cover from the main housing. The reduction gear assembly will be visible inside. Note the position and orientation of all shims and spacers for proper reassembly.
8. 8

   Remove reduction gear assembly
   Remove the reduction gear retaining hardware including any snap rings or circlips. Carefully extract the reduction gear assembly from the housing, taking care not to damage bearing surfaces. Inspect the gear teeth for wear, pitting, or damage. Check all bearings for roughness or play. Replace reduction gear if wear exceeds service limits.
9. 9

   Inspect and clean housing
   Thoroughly clean the inside of the drive unit housing with solvent and lint-free cloths. Inspect all bearing races, sealing surfaces, and machined surfaces for damage or wear. Check magnetic drain plug for excessive metal particles. Replace output shaft seals regardless of condition.
10. 10

    Install new reduction gear assembly
    Install new or serviced reduction gear assembly into the housing, ensuring proper alignment with bearing bores. Install all retaining hardware including snap rings and circlips. Verify reduction gear rotates smoothly by hand without binding. Install any shims or spacers in their original positions.
11. 11

    Reassemble drive unit housing
    Apply thin bead of RTV silicone sealant to gear case cover mating surface per manufacturer specifications. Position gear case cover onto housing and install bolts. Tighten cover bolts in cross pattern in three stages to final specification. Allow RTV to cure for minimum 30 minutes before filling with oil.
12. 12

    Reinstall drive unit to vehicle
    Position drive unit on support fixture and carefully raise into vehicle, guiding it past chassis components and aligning with mounting points. Install all mounting bolts and tighten in stages, starting with locating bolts. Apply thread locking compound to specified bolts per service manual.
13. 13

    Reconnect coolant lines and electrical
    Reconnect coolant inlet and outlet lines to drive unit, ensuring proper routing and no kinks. Tighten coolant line fittings to specification. Reconnect all electrical connectors, verifying each connector is fully seated and locked. Reconnect any ground straps.
14. 14

    Reinstall halfshafts
    Guide halfshafts back into position on drive unit output flanges, ensuring left and right sides are correct. Install new halfshaft retaining clips if required. Install and tighten halfshaft bolts in star pattern to proper specification.
15. 15

    Refill drive unit gear oil
    Using gear oil hand pump, fill front drive unit through fill port with 1.5 quarts of 75W-90 GL-5 gear oil. Fill until oil reaches bottom of fill port opening. Install fill plug with new O-ring. Repeat for rear drive unit using 2.0 quarts. Ensure drain plugs with new washers are properly tightened.

Reassembly

1. Reinstall all four wheels and torque lug nuts to specification
2. Lower vehicle to ground
3. Refill EV motor coolant system and bleed air from cooling system per manufacturer procedure
4. Reinstall high-voltage service disconnect
5. Reconnect 12V auxiliary battery negative terminal
6. Clear any diagnostic trouble codes using Rivian diagnostic software

Verification

• Using Rivian diagnostic software, verify no fault codes related to drive units or high-voltage system
• Perform high-voltage system insulation resistance test to verify proper isolation
• Start vehicle and verify READY indicator illuminates without warnings
• Check for any gear oil or coolant leaks around drive units
• Perform slow-speed drive test (under 15 mph) in safe area, listening for abnormal noises from reduction gears
• Verify smooth acceleration and deceleration in both forward and reverse
• Check drive unit temperatures using diagnostic software after 10-minute test drive - should be within normal range
• Perform final inspection of all mounting bolts and connections
• Road test vehicle at various speeds and verify normal operation with no vibration, noise, or warning lights

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