Well it could be any number of things of course. As I've posted before I had a chirp or squeaking noise that seemed to be coming from behind the passenger seat but it turned out to be the right rear strut. I've also had a rattle like noise coming from just behind the drivers area by the window and the same area on the passenger side with the top up. The dealer fixed the one on the passenger side by lubricating a flap and some of the soft top components but not the drivers side. I've gotten the drivers side to become fainter and almost go away by lubricating the plastic pieces that form between the window and soft top and the flap inside the soft top. If you don't hear it with the top down, open the top about a third of the way so it is loose enough that you can see inside it with a flashlight. You'll see a flap about 3" x 4" that seems to keep some parts from rubbing on the plastic components near the window. Use some pure silicone to lubricate that a bit and the plastic parts as well. Don't get any on the soft op inside or out though. Look out for any excess anywhere. If that doesn't work and if you hear it with the top down it may be something in the suspension, a loose intake vent, etc. My wife thinks I should be committed when it comes to squeaks and rattles. ROFL about the post on it going away when she no longer rode in the passenger seat.