Fluid questionsi
 

Ave searched but didn't see this covered....I am going to swap fluid out on my 01 4.4

Front and rear diff. M1 75-90 do I need the limited slip formula? Also can I use redline D4 for my transfer case? Or any suggestions on transfer case. Thanks for your help!,

The X5 does not have limited slip differentials, so no, you don't need the fluid designed for limited slip applications.

Dexron III for the transfer case. D4 isn't a Dexron-certified fluid, but Redline says that they recommend it anyway, on the basis that it isn't important to be certified. You can believe them or not. I would use a real Dexron fluid myself.