Been a lurker for some time here-- wanted to post a resolution to an issue I had (and saw a few others have as well-- but now can't seem to find the relevant thread). I have a 2012 WK2 Summit --meaning I have the air suspension and that suspension TSB we've all read doesn't apply-- and have had a squeak/rattle emanating from the passenger side rear for some time. It got slowly worse over time. And when it got cold it would get REALLY pronounced. For quite a while I thought it was the back-passenger door but then I rode in the back while my wife drove and it was clearly coming from within the wheel housing.
Jeep dealer heard the noise (isn't that always the first hurdle!?) and spent some time taking apart the passenger back suspension isolating it down to a bad bushing. Warranty replacement of the bushing/suspension mount and the noise has gone away completely (for good I hope). Hope this helps someone else. Great forum guys! AND the WK2s are great-- my wife has a 2011 and I liked it so much I bought myself the 2012 -- this is my first issue of any kind with either.
Thanks for posting this - just starting to develop a squeak on the rear driver's side and going nuts trying to figure out where it's coming from. Trying to isolate the problem, ruled out the shocks or anything loose other than the stupid flashlight!