Differentials &Transfer case fluids
 

Coming up to 100k on my M62. Can anyone who has done these three fluid changes tell me if there was a noticeable difference in MPG afterwards. Did the car have an overall better feeling while accelerating. Just wondering if this is something that I should tackle on a weekend. thanks

No change in MPG, and I upgraded to Mobil synthetics, too.

The reason to do it is because it gives you peace of mind, and it is a relatively easy DIY.

Agree that it is a good idea to do them at that mileage, but can't see why you would feel any difference driving it, or impact the mileage.

The reason you do them at 100k is for better condition of the components at 200k, not immediately.

Hmmm. Didn't know you could youse Mobil 1 or Royal Purple or lucas. Thought you had to use BMW, or the Audi/VW fluid.

Diffs are just gear oil, as long as it is the correct viscosity, it will be fine.

Dexron for the transfer case, but only for pre x-drive.

If it is an x-drive, you need to use BMW fluid in the transfer case, as it is proprietary and there isn't a published spec for it.

You may be thinking of transmission fluid, since that has an Audi/VW spec for one of the transmissions.

Mobil 1 "European blend" 0W40 is an acceptable substitute for the BMW oil.

Heck, at the 6000 mile interval that I'm changing the oil, probably any synthetic is OK. You only really need "the good stuff" for extended drain intervals.

I used Mobil 1's ATF fluid in the transfer case and transmission, and their synthetic gear lube in the diff. I've got an '02, so no X drive.

FWIW, the oil in the transfer case and diffs was clear and looked good. Perhaps it did not need to be changed. The transmission fluid was black and very dirty.

:iagree: , with all of the above. Right On.

Had my diffs & transfer case, and manual trans fluid changed at ~65k miles: all looked very good to my eyeball and, my Indie doing the work agreed, but I guess it was worth it.
GL, mD

I changed mine with Royal Purple. Was not a tough job, took as long to go and get the fluids as it did to change them. I have also started using Royal Purple in the engine too. (5w30)

I did mine at 100K - figure it's better to change fluids just in case although it may or may not be necessary.

I used Amsoil ATF in the transfer case and synthetic gear oil in both diffs. No difference in feel or mpg or anything that I could tell.