From ECS Tuning comes a very comprehensive kit for servicing your differential using Redline 75w90 performance gear oil. Everything down to the seal is included. Servicing your differential is important to extend it's life and to keep it operating as it should.
The kit includes:
Genuine BMW driveshaft seal
Genuine BMW fill bolt (no drain bolt is equipped on the vehicle)
2 Genuine BMW large dust shields
2 Genuine BMW small dust shields
2 quarts of Redline 75w90 severe duty gear oil
2 Reinz axle seals
For draining the fluid, you will need a transfer pump. ECS Tuning has an extensive selection of tools. If you need a transfer pump simply go to the drivetrain section under maintenance.