Hi
when i put my lorry into revser it jerking (jumping) when you let the clutch out slowly it starts jerking but it doesn't do in it in any other gear its only just started to do it.
Put the lorry in top gear and with thew brakes ON slip the clutch for a minute or so, then all should be well until thre next time it happens, you either have dust or more likely a little oil on the friction plate this will burn it off and make it smooth again. it only happens in reverse because it is such a low gear but in time it will happen in first as well.
Cheers
Phil