My 1982 - 320i seems to be too loud, when I'm driving 65-75 mph. At 55 the motor hum seems to be normal but as I increase speed the interior noise becomes much loud and not at a steady increase. I've checked the engine mounts and they seem to be intact. Any suggestion on what next? I'm thinking that rubber connector between trannie and driveshaft maybe the source. I've had this noise for about 8 years. As I've gotten older it's finally really annoying me.