BMW uses automatic transmissions from ZF and GM. Some of them use Dextron and some of them don't.
It isn't possible to generalize what works where. e46 3 series used 4 different fluids. Only one of them was Dextron. Some e36 323s (or was it 325s) used both GM and ZF transmissions.
For some transmissions it would be ok to drain and refill with Dextron 6. Others not.
Find out what is specified for your car. You may have to look for a tag or at the transmission. Then look up what cross-references to your factory fill. Try manufacturers websites or maybe search/ask on bobistheoilguy
Last edited by Andrew*Debbie; 11-21-2011 at 10:44 PM.