I have a 1988 750iL and am having some problems with vibration at certain rpms then smoothing out as acceleration continues. What kind of symptoms are given when one has bad rear transmissions mounts. I live in Germany and took it to the BMW dealer who stated that I need a new auto.transmission. He said the clutches in the transmission were bad. Is it possible that I just need new rear transmission mounts? I had the driveshaft replaced last year.