I have recently renewed the joints in the front prop, so it's not that. The noise is only when taking up the drive, if I were to put the handbrake on, take up the drive and hold it there it would make the noise for ever except that I would burn out the clutch, but nothing is actually turning. If you have heard an automatic box slip when you put your foot on the brake and throttle pedal at the same time thats what it sounds like.