Renze
Elite Member
On most modern tractors, there is a built in one way clutch in the PTO. It allows the implement to rotate freely without transmitting any power back to the transmission.
Tractors from the early 60's and back, were direct connected between the implement and the transmission. Many many many seats have been stained brown when the clutch was put in and the tractor powered into the ditch, trees, barn, road, etc when the rotational energy of a bush hog powered the transmission.
This is actually because old tractors had a single PTO: when you pressed the clutch pedal, it would only disconnect the engine from the rest of the transmission, but leave the PTO and wheel drive locked together. With a dual stage clutch, the PTO and gearbox are not locked together anymore when you press the PTO clutch.
I have never worked with tractors without dual stage clutches... talking 1965 and newer.