Maybe I'm just paranoid from reading about all the transmission problems with the LS, but I am wondering if I should be concerned by a vibration that seems to come from the transmission at very low speeds. The sensation is almost like a shudder, similar to when you try to start in too high a gear in a manual transmission car. The problem doesn't seem to be the engine, because the tach shows over 1200 rpms. Is this how the transmission problems in this model first manifest themselves? Or is this considered normal for this car? The car has less than 500 miles; If this is a problem, I'd like to get it documented and fixed now rather than have it be a bigger problem later. Thanks..