2007 JK 4dr-X with 2in BB and 33in MTR's with less than 8k miles. I heard a rattle underneath the front end while I was driving last night. I crawled underneath and saw that the nuts holding the upper swaybar links to the swaybar had backed almost completely out. I was able to tighten the passenger side with no problems. The driver's side must have been loose for a while (don't know why I never heard it before) because the stud that screws into the ball joint was worn as smooth as glass in the middle. That nut, therefore, could not be screwed back in.
I have never messed with the swaybar upper links, only the lower, so I have no idea what caused them to come loose. Give yours a looksee and make sure you don't have to make a trip to the dealership over something simple like I'm about to.
To make matters worse, when I set up the appointment to take my Jeep in, I told them what the problem was and asked them to make sure they have the part in stock. I was told that they don't have the part, and they can't order it until they see for themselves!!!
I understand why, but it does not make me feel any better.