Twin Motor Unit Fluid Replacement

This is an easy DIY. You will spend more time removing and re-installing the underbody splash shield than replacing the fluid.


  • 3 bottles of DW-1 ATF
  • Two crush washers, Part # 94109-2000


  • ┬áT30 Torx bit
  • 10mm socket
  • clip removal tool
  • 3/8″ square drive ratchet or breaker bar or impact wrench
  • Torque wrench
  • Drain pan, 1 gallon or larger
  • Fluid transfer pump, syringe, or other method of pumping fluid through fill hole. You can find these at most auto parts stores or Amazon.


  1. Raise car.
  2. Using T30 Torx bit, remove the corner air deflectors.

  1. Using T30 Torx, 10mm socket, and clip remover, remove the bolts and one clip holding the splash shield. Remove shield.

Once you’ve removed the shield, the TMU will be visible, as will the two plugs:

  1. Using 3/8″ square ratchet/breaker bar/impact wrench, remove the fill plug. (Always remove or at least loosen the fill plug before removing drain plug.)

  1. Place drain pan beneath TMU. Remove drain plug.

  1. Once fluid is drained, re-install drain plug using new washer. Torque to 35 lb-ft (47 N-m).
  2. Add DW-1 ATF through fill hole until fluid starts to dribble out (about 2.5L) using whatever device you have.

This is something I made a while ago, and uses compressed air.

Stop once fluid starts dribbling out the fill hole.

  1. Using new washer, re-install the fill plug. Torque to 35 lb-ft (47 N-m).
  2. Re-install the splash shield and air deflectors. Torque bolts to 7 lb-ft.