Mobil 1 75W-140 in the transmission and in the FD

[FM696969]

i've been using Mobil 1 75W-140 in the transmission and in the FD for the last 18,000 miles.

i know bmw says to use 75w-90 on the final drive, but i've been filling it with Mobil 1 75w-140, with no problems ,no leaks, no noises from the final drive.

any concerns?

[Optimus Prime]

I used Mobil 1 in my tranny and FD and the tranny didn't seem to like it. I went back to BMW brand and it's been fine since then.

If everything seems fine to you with Mobil 1, then I wouldn't change it. If you're looking for other alternatives, I've heard good things about Redline.

[challey]

OP --
Did you use 75W-140 or 75W-90? Just curious 'cause I'm about to do my 12k service and want to switch to synthetic.

[jm1515]

i've been using Mobil 1 75W-140 in the transmission and in the FD for the last 18,000 miles.

i know bmw says to use 75w-90 on the final drive, but i've been filling it with Mobil 1 75w-140, with no problems ,no leaks, no noises from the final drive.

any concerns?

Personally, I think -140 is too heavy for the FD.
I've read about foaming, oil leaking thru the vent (probably overfill ) etc, but then again I've read posts just like yours, sooo....YMMV.

I switched to BMW Synth 75w-90 in both tranny and FD at the 600mi and then to M1 when I did the 6000mi.

I like the way my tranny shifts, and the FD seems happy too...

[Optimus Prime]

OP --
Did you use 75W-140 or 75W-90? Just curious 'cause I'm about to do my 12k service and want to switch to synthetic.

I believe it was the 75W-90. The shifting was really crap and it just didn't feel right. My mechanic told me he has had several other oilhead riders with the same experience and he switched me back to BMW straight away. Of course, YMMV.

[johnt650]

I have been using Amsoil 75-90 in the FD and went to Mobil 1 in the 75-140 for the tranny. All seems to be fine.