swap sides. they're the same and running in a different direction puts the joints on new surfaces. and if the clunk moves to the left, you were right. btw, had an sl years ago with a clunk on reverse then forward. the rotor on the rt rr wasn't bolted to the hub and you could see the hub move, making the noise and the rotor clamped by the caliper. the wheel doesn't trap the rotor as well as i thought. good luck, chuck.