Don't trust any sales rep at a local auto parts store that says his generic fluid is the same as the specific BMW fluid. Ask him what spec it meets (since BMW doesn't publish the X-drive fluid spec, should be interesting to hear his answer).

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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