Fairly sure its not the clutch, as the gearbox selects gears fine and the clutch does what it should. There is a noise as if a tooth is missing on something on the final drive, as it picks up with the road speed not engine speed and it does it in all gears on and off the power. Its possible to make the noise nearly stop when you feather the throttle just right, so the gearbox is effectively not under any load at say 30mph on flat ground. I changed the oil in the box just to be sure, and although it was a bit passed it, it was not the worst I've seen and there was enough in there with no chunks of metal in it either!
I've not seen a problem like it before, as most boxes I've seen either make a high pitched whining noise if say the diff is a bit tired for instance, or you can make the noise go away depending on what you do with the clutch, normally pointing at the release bearing.
Anyway, I've rambled on long enough, this should probably go in the technical section rather then the newbie now! But let me know what you think either way, or feel free to move this across to the relevant section.
Charlie
