I have noticed this for a while but it is getting increasingly annoying (either it has gotten louder or I am getting more aware of it). When the roads are bumpy and when I make a turn, the roof (from the sunroof area to the back) makes a cracking noise (like when people walk on dry wood floors). I went to inspect the roof by touching every part of it and I don't see anything is lose......anybody know how to fix this?