the car has 135,000 miles, and has only been to the dealership for service. so, i'm assuming that the tranny fluid has never been changed since they consider it "lifetime". now the quandary, do i change the fluid now or just let it go? i have had advice for leaving it and for changing it. a friend of mine has a aamco transmission shop, and he says that if it hasn't been changed consistently, then to let it go, as long as it is not low on fluid. he says a lot of people come into the shop, not bmw's, with a 100,000 miles or so on a tranny, and they service the tranny, and then all of a sudden, they start having slippage problems. any one have some bmw advice?