Oh dude, your super late in responding to that thread lol, i've already fixed the problem it was the rear control arm (track Arm). the ball joint wears out and rattles, hard to detect by looking at the parts. A site sponser sells a set of adjustible track arms for under 300 a set, which is better than the just under 400 price the dealer wants for just 1 arm.
Heres the link and information for the Repair on the Rear Upper Control Arm Track Arms.
DIY - Replace Rear Upper Control Arms (Track Arms)