Transfer Case Fluid
 

I wonder why there is a specific transfer case fluid that runs almost 50 bucks when redline D4 ATF works just fine? This has been one fluid i've been real hesitant to change but with my X almost at the 100k mark, i'm concerned about its condition.

Where do you get the information that Redline D4 ATF is an acceptable substitute?

ATF is fine for models up to 2003, but with the xdrive transfer case fitted from 2004 onwards, the recommendation is to use BMW fluid.

.......................

I wonder if there is a substitute for this BMW fluid...

For only $50, it's not worth the time or risk to find an alternate. I would just use the BMW fluid if you need to change it.

:iagree:

Word. It would be different if the fluid was changed every 7500-15000 miles, but 100000 miles, I'd go for the BMW stuff. Peace of mind.

Daniel

What is the change out interval recommendation for the xfer case fluid? Tech I spoke with recommended doing the xfer case fluid over the diff's.

I just hit 60k

Personally, I would do it at 60,000 (Inspection II) or at 100,000 (because it is a round number).

There is a difference between the 2000-2003 transfer case, and the x-drive transfer case fitted from 2004 on. The earlier one is no more critical than a diff, in my opinion. It is a sealed unit, with a chain. If it isn't leaking, and you aren't fording deep water, I would leave it for a long time and not worry about it. For the later version, there are clutch plates and now there is more of a reason to change the fluid, as the friction characteristics of the fluid can vary over time. This is the reason to use the BMW fluid, because it has friction modifiers that we don't know the spec for. 60,000 miles still seems like a reasonable interval.