I have a 6830 premium power quad here that won't allow me to change the range without significant force. The shuttle works fine and so does the clutch, not jerky or jumpy. I just can't get the tractor in or out of gear easily. It doesn't seem to make any difference if the tractor is stationary, hot or cold. This problem has gradually got worse these last 12mths. Anyone any idea what my problem may be? TIA