[Razorback1980]

A throw out bearing can rattle under two circumstances. The first (which is the worst) is it makes a noise when the clutch is pressed in. This means the bearing has rough surfaces on the race and is about to give you trouble. This obviously isn't the situation with yours. The second time it can make noise is it's not being used (clutch is out) and it's rattling around in there because there isn't any pressure on it. The thing to try here....make the car have the noise and then just put your toe on the clutch and push it down about a half inch or so until you feel a light pressure. This moves the throw out bearing into the pressure plate and stops it from bouncing around. If the noise quits, then that is the problem and we can find some ways to keep the bearing just a little tighter so it doesn't rattle. If that doesn't make the noise stop, the throw out bearing probably isn't the problem.