It's not the top or side plastic interior trim around the rear hatch .. I have taken those off and left them off .. noise is still there... looked at the trim on the lower half trunk door (not the upper door) and took that off (what a pain to do this btw)... Put it back on with some foam etc and noise is still there if not seemingly a little less... also drove with the rear hatch "popped" open and the noise is still there.. Drove with the rear luggage floor elevated and still there... I haven't removed the lower trim on the rear hatch that is next... maybe it is something outside the car... ?