Can you narrow down WHERE the noise is coming from? Sometimes it may sound like its from the rear when it's from the front...but if you can feel it on the floorboards that could be a shock gone bad or loose mount, loose spring, broken torsion bar strut (did that on my rubicon-took months to find it!) also, if there is the weight of a passenger, does it do it? Can you get a friend and go out in a parking lot, make lots of left hand turns with them in the jeep and out of the jeep to see what they hear and where it might come from? So many moving parts...so little information. But something you definitely need to track down!