Subframe Assembly - Rear (Remove and Install)

FRT No: 30010201

Note: Loosen suspension fasteners by hand, then use a cordless electric drill with a 3/8 in drive adapter and a 3/8 in drive air ratchet wrench.
Warning: Only technicians who have been trained in High Voltage Awareness are permitted to perform this procedure. Proper personal protective equipment (PPE) and insulating HV gloves with a minimum rating of class 00 (500V) must be worn any time a high voltage cable is handled. Refer to Tech Note TN-15-92-003, "High Voltage Awareness Care Points" for additional safety information.
Warning: If the vehicle has air suspension, activate "Jack" mode on the touchscreen before raising and supporting the vehicle.

Removal

  1. Prepare the vehicle for lifting:
    1. Air suspension vehicles only: Put the vehicle into Jack mode.
    2. Put the vehicle into Tow mode.
    3. Support the vehicle, but do not lift it at this time.
  2. Perform the vehicle electrical isolation procedure (refer to procedure).
  3. Remove the rear wheels (refer to procedure).
  4. On both sides of the vehicle, remove the nut that secures the shock absorber to the knuckle (torque 140 Nm), but do not remove the bolt yet.
  5. On both sides of the vehicle, loosen the bolts (x2) that secure the brake caliper to the knuckle (torque 120 Nm). Remove and support the calipers.
    Caution: To avoid damage to the brake line, the brake caliper must be supported at all times.
  6. Remove the park brake calipers (refer to procedure).
  7. Remove the mid aero shield (refer to procedure).
  8. Remove the subframe shear plates by removing the nut (torque 35 Nm), clips (x2), and screws (x3) (torque 6 Nm) that secure each shear plate to the subframe.
  9. If equipped, remove the screws (x2) that secure the rear skid plate to the subframe (torque 10 Nm).
  10. Large drive unit only: Remove the bolt that secures the coolant nipple to the coolant manifold (torque 6 Nm).
    Note: If the drive unit is being replaced, apply lubricant to the O-ring and transfer the nipple to the new drive unit.
  11. Release the clips that secure the HV cables:
    • Large drive unit: 2 clips to the subframe
    • Small drive unit: 2 clips to the body
  12. Disconnect the subframe harnesses from the body harness.
    • Vehicles built through September 2014: 4 connectors at the back of the rear subframe
    • Vehicles built after September 2014: 3 connectors above the RH side of the rear undershield
  13. On the RH side of the drive unit, disconnect the logic connector.
    • Large drive unit:
    • Small drive unit:
  14. Release the HV inverter cables (x2).
    • Large drive unit:
      1. Release the bolt that secures the drive inverter cover (torque 3 Nm).
      2. Remove both O-rings from the drive inverter cover and discard.
      3. Release the 2 fasteners that secure the HV cables (torque 9 Nm). Do not remove the cables at this time.
    • Small drive unit: Remove and discard the 4 screws that retain the HV cables (torque 7 Nm). Move the cables away from the drive unit.
  15. Small drive unit only: On the top RH side of the drive unit, release the ground strap from the drive unit (torque 6.5 Nm).
  16. If the drive unit is being removed, drain the gearbox fluid (refer to procedure).
  17. Drain the coolant from the drive unit.
    • Large drive unit: Clamp and release the hoses from the transmission and drive inverter.
    • Small drive unit: Clamp and release the hoses from the T-junctions on each side of the drive unit.
      Note: During removal of the subframe, 2 coolant hoses remain attached to the drive unit.

      LH side

      RH side

  18. Position the subframe fixture beneath the subframe.
  19. Carefully lower the vehicle so that the subframe table supports the subframe.
  20. Remove the bolts (x4) that secure the rear subframe to the body (torque 140 Nm).
  21. Carefully raise the vehicle approximately 3 in (75 mm) to gain access to the remaining attachments.
  22. On both sides of the vehicle, remove the bolt that secures the shock absorber to the knuckle.
  23. Large drive unit only: Release the remaining attachments to the drive unit:
    1. Pull the HV cables out of the drive unit.
    2. On the top RH side of the drive unit, disconnect the ground strap from the drive unit (torque 6.5 Nm).
  24. Fully raise the vehicle.
    Caution: While raising the vehicle, have an assistant monitor the underside of the vehicle. Ensure that no components are still connected and that there is sufficient clearance so that no components are damaged.

Installation

Installation procedure is the reverse of removal, except for the following:
Warning: Only use cleaning agents and solvents in a well-ventilated area.
Caution: Replace all Patchbolt(s).
Caution: Replace all nylon-insert locknuts.
Caution: Ensure that the bolt that secures the spring assembly to the knuckle is inserted towards the rear of the vehicle; the head of the bolt faces the front of the vehicle and the nut is tightened at the rear.
Caution: Only fully tighten suspension nuts and bolts when the vehicle is on a 4-post lift and the suspension is in the ride height position.
Note: Clean the affected areas before installation.
  1. Large Drive Units built before October 2014 only: Ensure that no harnesses or cable ties press into the acoustic padding upon reinstallation. Refer to TN-14-40-002, Noise Path for Motor Hum, for more information.
    1. Ensure that the 12V harness does not rest on top of either of the arches on the subframe.
      Note: Rotating the clip that secures the harness to the subframe helps to position the harness properly.
      1 Correct: Clip rotated.
      2 Correct: Harness routed inboard of subframe.
      3 Incorrect: Harness routed on top of subframe.
    2. Replace the cable ties that secure the HV cables when the subframe is reinstalled. Ensure that the 12V harness is routed beneath the cable ties.
    3. Ensure that the rearmost section of the 12V harness is secured to the subframe with cable ties. The harness should extend out from the rear of the subframe as little as possible.

      LH side

      1 Correct: The harness is secure and does not extend past the rear of the subframe.
      2 Incorrect: The harness is loose and extends past the rear of the subframe.

      Middle

      1 Correct: The harness is secured to the rear of the subframe.
      2 Incorrect: The harness is not secured to the rear of the subframe.

      RH side

      1 Correct:The harness is secure and does not extend past the rear of the subframe.
      2 Incorrect:The harness is loose and extends past the rear of the subframe.
    4. After connecting the HV cables to the drive unit, reach above the drive unit and pull the cables as far forward as possible.
      Note: When securing the HV cables to the subframe, ensure that the ratchets on the cable ties do not press into the acoustic padding
  2. After connecting the electric parking brake caliper harnesses, install plastic park brake connector covers.
  3. Small drive units only:
    1. Inspect the connector seals on the HV cables. If any are damaged, replace them.
    2. Apply P-80 emulsion to the connector seals.
      Caution: Do not apply P-80 emulsion to the HV terminals.
    3. Resecure the HV cables to the motor.
  4. Large drive units only: To prevent future water ingress, install new O-rings (1003784-00-A or later) on the drive inverter cover and apply Silicone Lubricant (1010251-00-A) on both before installing the cover. Insert the cover at an angle to prevent damage to the O-rings. Once the left (B+) O-ring is seated, rotate the cover into position.
  5. Remove the suspension from "Jack" mode. Set the suspension to Standard and allow the suspension to settle.
  6. Refill and bleed the cooling system (refer to procedure).
    Note: Check for coolant leaks while performing the refill and bleed procedure.
  7. Perform a four wheel alignment (refer to procedure).