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Differential seals on BMW e34

Cost: $30

Time: 3 - 4 hours

If you start to see some oil drops on your driveway that means that your BMW E34 - E32 - E28 is leaking. You have to determine if the leak is coming from the engine, the transmission, the output flange or the differential seals.
  • 8 mm hex socket and ratchet
  • 10 mm allen key for the differential drain and fill screws
  • jackstands and oil drain pan
  • 2 new snap rings and 3 flange oil seals
  • Oil seal puller, 2 bottles of Redline gear fluid and syringe.
1. Loosen the rear wheels bolts then place the rear of the car on jack stands. Clean the differential if there is a lot of dirt and oil around.
2. Grab your favorite oil pan and place it under the differential. Locate the drain plug and drain the differential oil.
3. Take a socket Allen key and remove all the bolts holding the half shaft. To do so, I place the car in 1st gear, loosen a bolt then remove the car from gear, turned the wheel, place the car in 1st gear again, loosen another bolt and so on...
4. once all the bolts are removed, place the half shaft out of the way and secure it with a piece of wire.
4. Pry the drive flange out with a big screw drive or a little pry bar. You have to use a piece of wood for leverage else you might damage the differential.
5. In the picture you can see the seal. To pry it out, you need a seal puller (cheap tool), don't even try with a screwdriver, there is a big chance that you won't be able to remove it...
5. Once the seal is out, in the picture you can see the snap ring. This is a good thing to change while you are changing the seal. Use a small flat screwdriver and remove it.
6. Install the new snap ring in place.
Snap rings failure will make the flange pop out on its own and you will loose a lot of differential fluid.
7. Lubricate the new seal with differential fluid and carefully install it in the differential. You can use a big socket and a small rubber hammer to make sure that the seal is in place. Be careful as you can VERY EASILY damage the seal... It is a good thing to buy an extra seal just in case.
8. Install the drive flange back in place until the snap ring engages.
9. The rest of the installation is reverse of removal. Don't forget to fill up the differential with fresh redline gear oil.
Recheck everything, lower the car and enjoy.