Differential Service

Service the electric drive unit differential by draining old fluid, inspecting components, and refilling with fresh Dexron VI ATF to maintain proper lubrication and cooling.

Warnings

Tools required

Parts

• Drain plug copper washer × 1 — GM 84889609
• Fill plug copper washer × 1 — GM 84889609

Fluids

• ACDelco Dexron VI ATF — 1.5 qt

Preparation

1. Park vehicle on level surface and apply parking brake firmly
2. Place wheel chocks behind rear wheels
3. Disconnect 12V battery negative terminal and wait 2 minutes
4. Raise front of vehicle and secure on jack stands at manufacturer-specified lift points
5. Remove plastic underbody shield if equipped to access drive unit
6. Verify vehicle has cooled to safe working temperature

Procedure

1. 1

   Locate differential service plugs
   Identify the drain plug on the bottom of the electric drive unit housing and the fill plug on the side of the housing. Clean the area around both plugs thoroughly with a rag to prevent contamination. Position drain pan directly under drain plug.
2. 2

   Remove fill plug first
   Using appropriate socket, loosen and remove the fill plug first before draining. This ensures you can refill the unit after draining. Inspect the copper washer on the fill plug and set aside for replacement. If fill plug is seized, do not proceed with drain until it can be removed.
   ⚠Always remove fill plug before drain plug to avoid being unable to refill the unit.
   Torque spec

   Fill Plug41 Nm (30 lb-ft)
3. 3

   Drain differential fluid
   Remove the drain plug and allow fluid to drain completely into the drain pan. This should take approximately 5-10 minutes. Inspect drained fluid for metal particles, debris, or unusual discoloration which may indicate internal wear. Remove and discard the copper washer from the drain plug.
   Torque spec

   Drain Plug41 Nm (30 lb-ft)
4. 4

   Inspect drain plug and magnet
   Clean the drain plug thoroughly, paying special attention to the magnetic tip. A small amount of fine metallic powder is normal, but large metal particles or chunks indicate potential drive unit damage that requires further inspection. Clean threads on both drain plug and housing.
5. 5

   Reinstall drain plug
   Install new copper washer onto drain plug. Thread drain plug into housing by hand until seated, then torque to specification using torque wrench. Ensure plug is properly sealed to prevent leaks.
   Torque spec

   Drain Plug41 Nm (30 lb-ft)
6. 6

   Refill with fresh ATF
   Using fluid transfer pump or funnel with appropriate length hose, add fresh ACDelco Dexron VI ATF through the fill plug hole. Fill until fluid begins to drip from the fill hole, indicating proper level. The unit requires approximately 1.5 quarts. Allow fluid to stabilize for 1-2 minutes and top off if necessary.
   ⚠Only use ACDelco Dexron VI ATF. Other ATF formulations or gear oils may damage the electric drive unit.
7. 7

   Reinstall fill plug
   Install new copper washer onto fill plug. Clean any spilled fluid from the housing exterior. Thread fill plug into housing by hand until seated, then torque to specification using torque wrench.
   Torque spec

   Fill Plug41 Nm (30 lb-ft)
8. 8

   Inspect for leaks and complete installation
   Wipe down the entire drive unit housing to remove any residual fluid. Inspect both drain and fill plugs for proper seating. Reinstall any underbody shields removed during preparation. Lower vehicle from jack stands.

Reassembly

1. Reconnect 12V battery negative terminal
2. Remove wheel chocks
3. Properly dispose of used ATF at certified recycling facility

Verification

• Power on vehicle and verify no warning lights or messages related to drive unit
• Test drive vehicle for 5-10 minutes, listening for unusual noises from drive unit
• After test drive, raise vehicle and inspect drain and fill plugs for any signs of leakage
• Check fluid level through fill plug opening - fluid should be at bottom of fill hole threads when level

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