spoke to a couple of people one reckong centre diff and oe reckons a chipped toot on a cog in gear box its tapping when driving and also in neutral wen the car is just idle,n it is fine there no noise at all i will find out tonight hopefully its a a uk 1999 impreza wagon turbo i am in scotland where would be the best place to get a gear box or centre diff if it is that and does any1 know a rough price i will be