crunch when clutching

[dr00]

did a search and couldnt find anything like this. ive got an rb25det in s13 with rb25det gbox. the gearbox is fairly buggered, crunching into second and a bit into third and fourth. i had it tuned on monday and it was running much better so i was giving it a fair bit more of a hiding than before and almost straight away i started getting a problem where if i rev it out in any gear and put the clutch in i get a nasty crunch. dont touch the gearstick at all it just crunches as the clutch goes in. can anyone give some idea of what the problem might be? other than this the clutch functions normally. it is a heavy duty 5 puck brass button.

to help the gearbox ive got a harder gbox mount, engine damper and redline lwsp oil.