Hi, I have a 2001 Selespeed 156 which has developed a 'crunching' sound when changing gear. It doesn't do it on every change , just when going between 2nd and 3rd and 3rd to 4th. All other gear changes are ok. I have no 'slipping' of the clutch and it drives fine apart from the crunching sound. Any ideas people? Thanks in advance. Alan.