I have a 94 530ia with 60k miles. I wasn't sure if the PO ever changed the tranny fluid, so I had a tranny service (complete seal, filter and other part replacement) My mechanic (BMW specialist, only works on them and races many M3's) told me to not change ALL of the fluid at one time, it might cause problems. I think he changed most of the fluid but left some original or something like that. It isn't lifetime fluid. BMW also reccomends 15,000 mile oil interval changes, so don't always listen to them. I would definetly look into some kind of fluid change/flush.