I'm new here, and found this site when trying to search and find an answer to my problem. 2007 Compass has a crunchy/rattle noise in the back seat area whenever I go over bumps, BUT when I put the two back seats down... there is NO NOISE! What could this be? Thank you so much.
Do you have a removable luggage cover that hooks onto the back seats?
I'm not an expert, but I've noticed a similar sound when the cover is retracted -- sometimes it doesn't seat properly, and you have to whack it to get it in place.
Just a guess . . . .