Front/Rear Diff and Tcase fluid spec?

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So far from what I have found after hours of reading and seeing no real proof. The spec for the front and rear diffs are the same. 75w90 and from what I understand must be a GL-4 ONLY. Correct me if I'm wrong there please. For the transfer case or "power divider" I am seeing the required spec only as "75W".
So school me on this please, I recently bought my 2011 E70 35i and have changed the oil/filter and replaced the transmission pan/filter and fluid. I need to get the transfer case fluid at least then the diffs. So what specs do they call for? I have a half a 5 gallon pail of Mobile 1 75w90 gear oil (I beleive its GL-4/GL-5 rated will have to check) Keep in mind this is soecifically for my 2011 35i X5. Please help me figure this out so I can buy some fluid and get it changed. I have plenty of Castrol Transynd, previously mentioned Mobile 1 gear oil, Rotella T6 but need to know the fluid needed for this unit. For that matter is the brake fluid dot 3 or 4? I'm a guy that is oretty good about fluid maintenance but I want to source the right spec' products.

[Attacking Mid]

You can use most any decent gear oil in the diffs. BMW specs 2 different fluids, but I've never seen evidence of there being any issue with just using any decent quality 75 or 80w-90. I use a full synthetic.

The transfer case is much more particular. You want to use a fluid that meets the DTF1 spec for BMW. There aren't a ton of choices: BMW, Shell, Rock Oil, Ravenol, and there may be some others that re-label the Shell product (I found some from Febi).

AM.

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Thanks for the info. I am finding TCase fluid is hard to come by or super jacked up prices on the usual common online retailers(No dealer in my town). BMW does seems to make any fluid specs other than engine oil super hard to find. The BMW fluid says 75W on the bottle, at least in the pictures online. But thats it really kind of leaves it to the imagination.
So I just want to confirm then 75W90 gear oil for front and rear diff is fine then?

[Attacking Mid]

https://www.fcpeuro.com/products/bmw...ll-83222409710

$30 is about as cheap as it gets. It contains unicorn tears, afterall. ;-)

Yes, 75W-90 synthetic gear oil is fine in both differentials. You can probably even get away with conventional oil, but would need to change it more frequently. Here's what I have been using due to being an excellent value: https://www.autozone.com/greases-and...art/443149_0_0

AM.

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That $30 at Fcp turns in to a lot more after shipping across the border fees and all that up to me. That's one of the reasons I've been doing my due dillegence before putting the wrong fluid in this thing. Thanks for the info and confirmation on the gear oil. I still have half a 5 gallon pail of Mobile 75w90 in the garage. Much appreciated. Can't really find a reasonable way to order the tcase fluid without paying ridiculous prices so I might have to find a reason to make the 2.5 hour trip there and back to the dealer one day if I don't figure something out soon.