You people have saved me a load of money, and I'm hoping you can again. I have a 91 300CE. It runs great, but when started from cold it rumbles like a bad diesel. This rumble only seems to happen when its in D or R with my foot on the brake. If I put the gearbox to P or N, it doesnt happen, or if I apply some throttle, it doesnt either. Also, when I brake hard, the gear selector seems to rock backward about 1/2 inch. Is this normal? Is this most likely an engine problem, or a tranny problem? Or just a simple mounting? Any help would be appreciated.