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.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue