Drive Unit Fluid Change

This procedure drains and refills the electric drive unit fluid in the 2023 Chevrolet Bolt EUV, requiring removal of protective covers and undercarriage access to service the transmission-integrated motor assembly.

Warnings

Tools required

Parts

• Drive unit drain plug seal × 1 — GM 24287861 or equivalent
• Drive unit fill plug seal × 1 — GM 24287862 or equivalent
• Undertray hardware kit (if damaged) × 1 — Use OEM specification

Fluids

• ACDelco Dexron VI ATF — 13.5 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Turn off vehicle and remove key fob from vicinity to prevent accidental startup
3. Allow drive unit to cool for minimum 2 hours if vehicle was recently operated
4. Disconnect 12V auxiliary battery negative terminal and wait 2 minutes
5. Verify high-voltage system is de-energized using insulated multimeter at service disconnect
6. Remove high-voltage service disconnect located under rear seat (orange connector)
7. Wait mandatory 5-minute de-energization period after service disconnect removal
8. Raise vehicle on lift ensuring vehicle is level front-to-back
9. Support vehicle on safety stands if using floor jack
10. Remove front undertray and splash shields to access drive unit

Procedure

1. 1

   Remove protective covers and access panels
   Remove the front undertray cover screws using 10mm socket. There are approximately 12-15 screws securing the undertray. Carefully lower the undertray and set aside. Remove the drive unit access cover by removing the cover screws.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
2. 2

   Locate and clean drain plug area
   Identify the drive unit drain plug on the bottom of the drive unit housing (18mm hex). Clean the area around the drain plug thoroughly to prevent contamination from entering the system during service. Position drain pan directly below drain plug with minimum 15 quart capacity.
   ⚠Ensure drain pan is properly positioned as fluid will drain quickly once plug is removed.
3. 3

   Drain drive unit fluid
   Using 18mm socket, slowly loosen the drain plug approximately one turn to verify no excessive pressure. If fluid sprays out, allow pressure to equalize before continuing. Completely remove drain plug and allow fluid to drain completely. This will take approximately 15-20 minutes. Inspect drained fluid for metal particles or contamination. Remove and discard the old drain plug seal.
   ⚠Fluid may still be warm. Wear fluid-resistant gloves and allow fluid to drain at its own pace.
4. 4

   Inspect and reinstall drain plug
   Inspect drain plug threads and magnetic tip for excessive metal particles (light coating is normal). Clean drain plug thoroughly. Install new drain plug seal onto drain plug. Thread drain plug into drive unit housing by hand to prevent cross-threading, then torque to specification using 18mm socket and torque wrench.
   ℹ️The drain plug torque uses the Mounting Bolts specification of 27 Nm (20 lb-ft). Do not overtighten as this may damage the aluminum housing.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
5. 5

   Locate and prepare fill plug
   Locate the drive unit fill plug on the side of the drive unit housing (13mm hex). Clean the area around the fill plug thoroughly. The fill plug is also the level check plug - fluid level is correct when it reaches the bottom of the fill plug hole.
   ℹ️Verify vehicle is level before proceeding with fill procedure. An unlevel vehicle will result in incorrect fluid level.
6. 6

   Remove fill plug and prepare fluid transfer
   Using 13mm socket, remove the fill plug and seal. Set up fluid transfer pump with ACDelco Dexron VI ATF. Insert pump nozzle into fill plug opening. Verify you have the correct fluid type - only Dexron VI is approved for this application.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
7. 7

   Fill drive unit with fluid
   Using fluid transfer pump, slowly add ACDelco Dexron VI ATF into the fill plug opening. Add fluid until it begins to drip from the fill plug hole, indicating proper level has been reached. This should require approximately 13.5 quarts total. Allow fluid to settle for 2-3 minutes and verify fluid continues to drip from fill hole at a steady rate.
   ⚠Do not overfill. Excess fluid can cause drive unit damage and seal leakage. Proper level is when fluid just begins to drip from fill hole.
8. 8

   Reinstall fill plug
   Install new fill plug seal onto fill plug. While fluid is still dripping slowly from fill hole, thread fill plug into housing by hand, then torque to specification using 13mm socket. Wipe away any spilled fluid from drive unit housing.
   ℹ️Install fill plug while fluid is at correct level to prevent air pockets in the system.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
9. 9

   Inspect for leaks and reinstall covers
   Carefully inspect both drain and fill plugs for signs of leakage. Wipe area clean and observe for 2-3 minutes. If no leaks are present, reinstall the drive unit access cover and torque cover screws to specification. Reinstall front undertray and torque all undertray cover screws to specification.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
10. 10

    Reconnect high-voltage system
    Reinstall high-voltage service disconnect under rear seat, ensuring orange connector clicks fully into place and lock lever is secured. Reconnect 12V auxiliary battery negative terminal and torque to specification. Clear vehicle from lift or jack stands.
    ⚠️Ensure high-voltage service disconnect is fully seated and locked. A partially connected disconnect can cause arcing and system damage.
11. 11

    Perform system initialization
    Turn vehicle to ON position (do not start). Verify no warning lights related to drive unit or high-voltage system appear on instrument cluster. Cycle vehicle through READY mode and verify drive unit operates normally. Monitor for any unusual noises or vibrations.
    ℹ️Some vehicles may require a brief learning period after fluid change. Initial operation may feel slightly different for the first few miles.

Reassembly

1. Verify all undertray panels and covers are securely fastened
2. Confirm no tools or parts were left in engine bay or under vehicle
3. Double-check torque on all fasteners, particularly drain and fill plugs
4. Ensure high-voltage service disconnect is properly installed and locked

Verification

• With vehicle in READY mode, verify no warning lights appear on instrument cluster
• Test drive vehicle for 5-10 minutes, including various speed ranges and acceleration rates
• After test drive, raise vehicle and inspect drain and fill plugs for any signs of leakage
• Verify fluid level by briefly removing fill plug - fluid should be at bottom edge of fill hole when at operating temperature
• Check for any unusual noises, vibrations, or performance issues during operation
• Properly dispose of used drive unit fluid according to local environmental regulations

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