The squeak I am referring to occurs when letting out the clutch to move off from a stop, usually only when taking off vigorously. It is a dry tinny metallic sound that comes from under the car (not the pedal) It seems to be related to a newly replaced clutch, in my case a Sachs. I have posted about it previously, and have heard from others experiencing a similar problem.

While looking at a new clutch a friend was preparing to install in a 142E race car, it came to me. The noise is caused by movement between the halves of the clutch disc. On a stock disc there is a hub, with a splined hole at the center, connected to the actual disc with the linings on it in such a way that they can rotate a little relative to each other, with coil springs in between to cushion the takeup of the clutch (a racing clutch disc is one piece, as smoothness of engagement is less important than durability in that application) The cause of the noise is the movement between these parts, which doesn't occur if you drive off gently enough. Unfortunately, I can't think of a cure, as it does not seem like a good idea to try to lubricate the area---centrifugal force would quickly spread whatever was used onto the linings.

Though annoying, I don't think it is a reliability/durability issue, unlike a dry release bearing, which was the other possibility I had thought of. The circumstance under which it occurs makes the disc itself the prime suspect---if it was the release bearing, it would do it every time the clutch was used.