When the transfer case fluid requires changing the vehicle will tell you so. The computer monitors transfer case clutch engagement pressures and times, and flags a fluid that is out of spec.

Do you believe that changing the fluid early will extend the life of the transfer case?

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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