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Acura MDX: How to Change Differential Fluid

Replacing the rear differential fluid periodically in your Acura MDX is critical if you want the get good mileage, and keep the AWD operating properly.

By Bassem Girgis - May 17, 2016

This article applies to the Acura MDX (2001-Present).

The rear differential fluid is part of the regular maintenance that you need to do; typically, about every 30,000 miles. Most people overlook this gear oil, but it works as a lubricant to keep the gears turning freely in the all wheel drive system. If you have a later MDX, and didn't choose the AWD option, you don't have a differential in the back to worry about. Read on to learn how to replace the rear differential fluid.

Acura MDX: How to Change Differential Fluid

Materials Needed

  • Tire iron
  • Drain pan
  • 3/8 extension
  • Allen head socket
  • Fluid pump
  • Torque wrench
  • Differential fluid

Step 1 – Remove spare tire

The spare tire on the MDX is under the rear of the car. To remove it, open the trunk, then pop the plastic piece covering a nut. Use your tire iron to turn the nut counter-clockwise, this will lower the spare tire like an elevator. When the spare tire is low enough, turn the piece holding it in place side ways to remove it from the tire. Removing the spare tire will give you the proper room to work on the rear differential.

Lower spare tire
Figure 1. Lower spare tire.

Step 2 – Remove fill plug

Before draining the rear differential, you have to remove the fill plug. The last thing you want is to drain the rear differential fluid, then fail to remove the fill plug, in which case you will be stuck. The fill plug is inside the hole in Figure 2. Use a 3/8" ratchet extension in the corresponding square hole to remove it.

  • Fill plug in located behind this hole in the crossmember
    Figure 2. Fill plug is located behind this hole in the crossmember.
  • Remove fill plug
    Figure 3. Remove fill plug.

Step 3 – Drain rear differential

Place a drain pan under the drain plug, then use your Allen head to remove it. Let the fluid drain completely into the drain pan, then close the drain plug and torque it to 35 ft/lbs.

Drain rear differential fluid
Figure 4. Drain rear differential fluid.

Step 4 – Pump fluid into rear differential

Use a fluid pump to pump three quarts into the fill hole. On later model MDX with the SH-AWD system, you may put as much as three quarts in. You will know it is full because gear oil will begin to drip out of the fill hole, as long as you have the vehicle on jacks or sitting on the ground level. When you're done, tighten the fill plug, then reinstall the spare tire in its place.

Pump fresh fluid into rear differential
Figure 5. Pump fresh fluid into rear differential.

Featured Video: How to Change Rear Differential Fluid

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