I had the same thing but on the drivers side. Through a lot of trial and error I tracked it down to the lower control arm bushings. I had 90k miles on it at the time. I wound up replacing the upper control arm (because I tore the boot on the ball joint when I raise the vehicle and let the back axle hang for a week...bad idea BTW), and then I changed the lowers. I don't know if anyone else got a notice, but I got a notice from Chrysler saying that they were changing out the lowers on some vehicles due to corrosion concerns. I had already changed mine so I threw the notice away but it might be worth a call to your local dealer to see if you qualify.
