Hello folks. After my mammoth drive from Kent to Munich in the Caterham, my mileage has reduced significantly, but now that I'm more comfortable pushing on in the car I've noticed a significant crunch when changing up from 1st to 2nd gear. The issue is only when the revs are high, and the speed with which I change gear doesn't seem to reduce the issue. Additionally, it is only when changing up from 1st, and not when changing down from 3rd. A quick search of the forum led me to this thread which suggests a threshold of 4.5k rpm but I haven't checked my car against this. I too have the 5 speed box, but i don't know what oil has been used in it. This thread doesn't seem to offer a conclusion to the problem, so i'm looking for any suggestions or experience others might have? Cheers, Pete.