Friend of mine asking me to post this up to see if any of you have some ideas.

My mates sister has a bog standard Focus ST, but its developed a high pitch whine from the box bell housing. Its consistent no matter what, but only when its hot. No sound at all before the engine warms up. The thrust bearing was completely shagged but replaced, the clutch has no signs of excessive wear and the starter motor was removed while running. But none seem to be the cause for the noise.

I thought perhaps flywheel related?

Any ideas guys?

Cheers!

Al