For the last month my 1.4 has developed an odd whine its hard to pinpoint but seems to come from somewhere in the front left, it only does this when im accelerating in 5th and its like a sort of supercharger/turbo spooling up kind of noise (which does sound cool for a while until i realise it may be causing damage) it gets higher pitched/faster as i increase speed only in 5th gear tho. I was thinking some sort of gbox problem as it only does it in 5th above 50mph. can anyone help shed some light on this?