Mine was doing it everyday after work for a long time. It also does it when I'm parked in my driveway (at an angle). Anyway, I have been experimenting with the way that I park it at work and I swear that it has something to do with the transmission and/or drive train slack. Before, I would park at work (back in), then maybe go forward a little, stop, and throw it into park. It seems that when I back in, adjust by going forward, and then slowly cycle the gear knob from D to N to R to P rather than just quickly throwing into park; the clunk does not occur. From my observation, I think that either the transmission isn't going into park completely or that quickly throwing it into park creates drive train slack. I'm curious if anyone else has noticed this. Either way, when it does occur it surely sounds violent and it is definitely not normal.