I am so frustrated that this is occurring and making me feel unsafe. I hear the clunk when I put the car in gear in either drive or reverse. It also occurs when I accelerate or decelerate, when I am on and off the gas pedal. I had someone try to diagnose the problem, the car was put up on the lift and they thought it might be the transmission but everyone is scratching their head trying to figure it out. The car has also blown out white smoke when getting on the highway a few times when I have punched the gas a bit hard. I also had an issue when I first got the car and was parked up hill and went to put it in gear and it was in drive and it rolled backwards and I had to shut the car off and it then went in gear. I am getting extremely angry, bought the car used and it drove very nicely, now I am not feeling safe at all. Please someone shed some light on this situation or let me know if anyone else has had this problem or what it may be.