i have the same clunk also when i turn the wheel lock to lock. i was told it might be the front strut bearings have slop or sway bar might be loose. couldn't find the problem myself with a visual inspection. the car is going in the shop monday for a front brake job, front calipers not releasing all the way and the wonderful dealer put cheap as pads on the front and didn't turn the rotors.(there are glazed so bad i can almost see my reflection in them causing the pads to seat improperly)i hope the inside of the rotors are not scored to the point of no repairand must be replaced. anyways my mechanic is going to check out the steering clunk. i will let you know what i find out monday after i get the car back.
