My 2004 3.0 has 17mm normal (not allen) fill plug located on the driver side back corner just above where the pan meets the housing. The drain plug removal needs a Torx (like a star) drive bit T50 or T55 (I'm not sure). The fluid is Dextron VI BMW part 83222163514. 6 liters for dropping pan & fill. 4 liters if only drain & fill. This is for my 2004 3.0. Mostly same but doesn't mean exactly same for another 2004 3.0. Check it all out under the vehicle before you start. See this thread link. It has pics for 2001 3.0. My drain & fill plugs are like in these pics.
http://www.xoutpost.com/bmw-sav-foru...r-x5-3-0i.html