BMW E46 Differential Service – 2 Hours
Contrary to popular belief the BMW E46 differential does not contain a “lifetime” fluid fill, and should be part of a regular maintenance schedule.
Servicing the rear differential on the E46 3 series is one of the most overlooked maintenance items in the drivetrain…and arguably the most important. The rear differential has a heavy work load of transmitting the power generated by the engine and delivering it to the rear wheels.
This power from the engine (delivered to the differential by the vehicle’s driveshaft) is proportionally sent to the rear wheels depending on whether the vehicle is turning or driving in a straight line. The differential allows the rear wheels to spin at different speeds, adjusting the power to them and maximizing stability to the vehicle. If there wasn’t a differential on the rear of your BMW, you would loose control of the car everytime you sharply turned the steering wheel.
All of this power conversion puts an enormous amount of stress on the differential’s internal gears. If the internal gears are not continually lubricated in a fresh, high quality synthetic oil, they can fail. Signs of a failing BMW E46 differential are handling difficulties, grinding or “whining” noises and rear end vibration. Unfortunately if you are experiencing any of these symptoms, you will probably require a differential rebuild or replacement. Servicing your BMW E46 differential on a regular basis will help avoid driveline failure and a costly repair.
Required (must be replaced) – Order two plug gaskets. One for the fill plug and one for the drain plug.
|Differential Drain Plug Gasket||2||7119963355||Genuine BMW – 1 needed for both drain plug and fill plug|
Required – Differential holds approximately 1.5 quarts of oil.
|Differential Fluid 75w90 20012||2||20012||LiquiMoly syunthetic, 75w90|
Optional (replace if necessary) – Fill and/or drain plug.
|Differential Drain/Fill Plug||1-2||33117525064||Genuine BMW – works as both a drain and fill plug. Order 2 to replace both|
Tools and Supplies
14mm Hex Socket
Torque wrench – medium range
Fluid Transfer Pump
Drain pan – 5 gallon
- Jack and support your vehicle using the Four Corner Wheel Stand Method as shown in our article BMW Jacking and Supporting for Repairs and Maintenance.
- Locate the differential and its fill and drain plugs at rear of vehicle.
- Use a 14mm hex socket to remove the BMW E46 differential fill plug located at the top of the differential. Always remove the fill plug first when servicing your differential – you don’t want to drain it then find out you can’t remove it.
- Remove drain plug with 14mm hex socket. Allow differential to completely drain into 5 gallon drain pan.
- Replace gasket on drain plug with a new one. Reinstall drain plug and torque to 65Nm (48 ft-lb).
- Using a good fluid pump, fill the differential with 75W-90 synthetic gear lubricant until it overflows out of the fill hole. The differential will take approximately 1.5 quarts to fill.
- When differential is full, replace the gasket on the fill plug and reinstall. Torque plug to 65Nm (48 ft-lb).
BMW E46 Differential Service Finished
If you have any questions or comments, please feel free to contact us. And congratulations for Doing It Yourself!