Complete removal and reinstallation of the electric drive unit (motor/inverter assembly) from a 2023 Chevrolet Bolt EUV, including disconnection of high voltage systems, coolant lines, and mechanical mounting points.

Warnings

Tools required

Parts

• High voltage service plug seal/cover × 1 — Use OEM specification
• Drive unit coolant (DEX-COOL Orange) × 1 — ACDelco DEX-COOL
• Engine mount hardware kit × 1 — Use OEM specification
• Drive unit gasket set × 1 — Use OEM specification
• Axle seals × 2 — Use OEM specification
• Oil drain plug crush washer × 1 — Use OEM specification

Fluids

• ACDelco DEX-COOL (Orange) — 10 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect 12V battery negative terminal and wait 2 minutes for system capacitors to discharge
3. Remove rear seat bottom cushion to access high voltage service disconnect
4. Following GM high voltage safety procedures, remove high voltage service plug and install lockout device
5. Wait minimum 5 minutes for high voltage system capacitors to discharge
6. Use multimeter to verify zero voltage at high voltage connections before proceeding
7. Raise vehicle on lift to working height
8. Remove front wheels and set aside
9. Remove engine splash shields and underbody panels
10. Place coolant drain pan under vehicle and drain drive unit cooling system
11. Mark all electrical connectors and coolant hoses with tape for reinstallation reference

Procedure

1. 1

   Disconnect high voltage cables and inverter connections
   Wearing high voltage insulated gloves, disconnect the high voltage DC cables from the battery pack to the drive unit inverter. Remove the orange cable securing brackets and carefully route cables away from work area. Disconnect the three-phase AC cables between inverter and motor section. Remove inverter coolant lines at quick-disconnect fittings.
   ⚠️Verify high voltage service plug is removed and locked out before touching orange cables. Double-check voltage with multimeter.
2. 2

   Disconnect 12V electrical connections
   Disconnect all low voltage electrical connectors from the drive unit including: position sensors, temperature sensors, resolver connector, and 12V power connections to inverter control module. Remove wiring harness brackets and route harnesses away from drive unit.
   Torque spec

   Electrical Connector Bolts7 Nm (5 lb-ft)

   Sensor Bolts11 Nm (8 lb-ft)
3. 3

   Disconnect drive unit cooling system
   Disconnect remaining coolant hoses from drive unit heat exchanger and inverter cooling jacket. Cap all open coolant ports to prevent contamination. Remove coolant line mounting brackets from drive unit housing.
   ⚠Some coolant will drain from hoses. Have towels and drain pan positioned to catch spillage.
4. 4

   Remove drive axles from drive unit
   Remove axle hub nuts at both front wheels. Separate lower ball joints and outer tie rod ends to allow suspension to drop. Using pry bar or axle separator, carefully extract both drive axles from drive unit output flanges. Support axles with wire to prevent damage to CV boots. Note seating depth of axles for reinstallation.
   ⚠Do not allow axles to hang by CV joints. Support weight to prevent joint damage.
5. 5

   Support drive unit with transmission jack
   Position transmission jack or suitable support fixture under center of drive unit assembly. Adjust height so jack just contacts drive unit but weight remains on mounts. Secure drive unit to jack with straps or chains to prevent shifting during removal.
   ⚠Ensure jack is centered under drive unit center of gravity to prevent tipping when mounts are disconnected.
6. 6

   Remove front drive unit mount
   Remove bolts securing front drive unit mount to subframe. Remove bolts securing mount to drive unit housing. Carefully extract mount from between drive unit and subframe. Inspect mount for wear or fluid leakage and replace if necessary.
   Torque spec

   Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)

   Engine Mount-to-Block Bolts65 Nm (48 lb-ft)
7. 7

   Remove rear drive unit mount and support bracket
   Remove rear mount-to-subframe bolts and rear mount-to-drive unit bolts. Remove support bracket connecting drive unit to body structure. Lower transmission jack slightly to create clearance for drive unit removal angle.
   Torque spec

   Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)

   Engine Mount-to-Block Bolts65 Nm (48 lb-ft)
8. 8

   Remove AC compressor from drive unit
   Recover refrigerant from AC system using approved recovery equipment if not already done. Disconnect AC lines from compressor and cap immediately. Remove compressor mounting bolts and separate compressor from drive unit. Set compressor aside without stressing AC lines.
   ℹ️AC system recovery must be performed by certified technician using approved equipment per EPA regulations.
   Torque spec

   AC Compressor Bolts25 Nm (18 lb-ft)
9. 9

   Separate drive unit from subframe and lower from vehicle
   With all connections verified disconnected, carefully tilt and maneuver drive unit to clear subframe and body structure. Slowly lower transmission jack while guiding drive unit out from underneath vehicle. Watch for any remaining connections or interference points. Once clear of vehicle, transfer to engine stand or work surface.
   ⚠Drive unit is heavy and awkward. Have assistant guide unit during lowering to prevent damage to vehicle or unit.
10. 10

    Inspect and prepare for reinstallation
    With drive unit removed, inspect subframe mounting points, coolant passages, and electrical connector mounting areas for damage or corrosion. Clean all gasket surfaces on drive unit and mating components. Replace axle seals in drive unit output flanges. Inspect drive unit mounts for wear and replace as necessary.
    Torque spec

    Gasket Surface Bolts20 Nm (15 lb-ft)

Reassembly

1. Installation is reverse of removal with following critical points
2. Install new axle seals in drive unit output flanges before installation
3. Apply thin coat of grease to axle splines before inserting into drive unit
4. Ensure axles are fully seated in output flanges with snap rings engaged
5. Replace all gaskets and seals disturbed during removal
6. Torque all fasteners per specification table in proper sequence
7. Reconnect coolant lines ensuring quick-disconnects are fully locked
8. Refill cooling system with ACDelco DEX-COOL to proper level (10 quarts total system capacity)
9. Bleed air from cooling system per GM service procedure
10. Reinstall AC compressor and have AC system evacuated and recharged by certified technician
11. Reconnect all 12V electrical connectors ensuring positive engagement
12. Route high voltage cables in original positions and secure with all brackets
13. Reconnect high voltage cables to inverter with proper torque on connector bolts
14. Reinstall high voltage service plug ensuring proper seating
15. Reconnect 12V battery negative terminal
16. Perform high voltage system integrity test per GM service procedures before operating vehicle

Verification

• Use GM diagnostic scan tool to verify no high voltage isolation faults are present
• Verify cooling system is full and properly bled with no leaks
• Check all electrical connections for proper seating and secure mounting
• Verify drive axles are properly seated with no abnormal play
• Perform propulsion system test in PARK to verify motor operation without warning lights
• Test drive vehicle verifying normal acceleration, no unusual noises, and no warning lights
• Verify AC system operates normally if compressor was removed
• Recheck all mount bolt torque values after test drive
• Scan for diagnostic trouble codes and address any issues found

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