1. Raise The Car

First step is to raise the car. In order to properly fill the differential, the car must be perfectly level when re-filling later on. To do this, use 4 even jack stands or a lift. In this case we will be using the QuickJack 5000TL.

Fig. 1

2. Remove Fill Plug

Once the car is in the air, you can start servicing the differential. You always want to remove the fill plug first (14mm socket). This also applies when changing the oil in a transmission. Think about it, if you remove the drain plug and then strip the fill plug, you’ll be out of luck as your differential will be empty and you have no way of filling it. Now think of it the other way around.. much better situation to be in.

Fig. 1

3. Remove Drain Plug & Drain Old Oil

Remove the drain plug (14mm socket) and drain all of the existing oil from the differential. Have a pan underneath the car to catch the oil as it comes out.

Fig. 1

Fig. 2

4. Reinstall Drain Plug

Install the new drain plug (14mm socket) and torque to 45nm (33ft/lbs). Lubricate the gasket on the new plug with a little diff oil before installing.

Fig. 1

5. Fill The Differential

Pump new oil into the fill hole of the differential until it starts to overflow out of the hole (keep oil pan underneath). When it overflows, that means you have filled the differential to the max level. You don’t have to wait until it stops dripping completely before moving on to the next step. The differential should take a little over one liter to fill.

Fig. 1

Fig. 2

6. Reinstall Fill Plug

Install new fill plug (14mm socket) and torque to 45nm (33 ft/lbs). Like before, take a little differential oil and lubricate the gasket on the new fill plug before installing.

Fig. 1

7. Lower The Car And You Are Finished!

This is one of the easiest jobs you can do it and will last you another 50k miles on the F8x chassis. Although you probably won’t notice a difference, some owners do report smoother shifts after replacing their differential fluid.