So mine started this a couple of weeks ago. The temperature at night has been dipping into to 20's and it sits for four or five days at a time, I don't drive it everyday. When I start it on a cold morning the transmission sounds pretty rough, really just figured the oil is cold and it is what it is. But even after it warms up it has the supercharger noise...kinda like a bad ground on a radio, it sounds like its coming from the transmission area and not the engine compartment. crazy that there is no dipstick. Will make an appointment and see what happens.