my valver has started to slip out of 5th at around 4500rpm
did it once on the way back from blackpool a about a month ago
then when on way back from stoke i stopped and there was a lot of smoke coming out from what seemed to be the cat/manifold
today on way back from essex it slipped out say every ten minutes or so when at 4200 t0 4700 in 5th
at under 4000 it doesnt slip out at all
any ideas please?