My R11 from last year has some rattling bits going around inside the clubhead. It doesn't bother me when I'm swinging, but the driver doesn't sound the same anymore. It sounds like I'm hitting the ball with a hollow piece of wood rather than that high pitched crack that I normally get.
What should I do? Call TM for a replacement? Take it in somewhere to get it looked at? I'm disappointed, I only got this driver last year. Might give me an excuse to shell out for a Ping i20 though :).