i am having trouble with a mates 4x4, the car vibrates when up to speed, the intial problem was a drive shaft but my mate thought it was the transfer box, we changed this then fitted the right shaft, this took the original vibration away but now at around 3k revs the full car shakes about, my mate seems to think its the gearbox but i think we should fit the cars original transfer box just to eliminate whether its the new box or something else on the car....................... if anybody can point me in the right direction it would be really appreciated as i've never had much experience with these cars!!!