We recently sent our 1987 L2850 to the local dealer because we could nbot engage the pto. Grind grind etc. The 2 position clutch pedal would disengage the tractor when depressed 1/2 way and disengage the pto when fully depressed. It came back today backwards; pto 1/2 way down and tractor all the way down. Dealer says that's the correct operation. We bought machine new in 1987 and it's backwards for how it was in 87 Help