Below are images of JD trailer plows. A trailer plow is meant to be pulled by the tractor drawbar and transports on either 2 or 3 wheels. JD introduced factory hydraulic lift plows in 1946 (same time they introduced their new Powr-Trol on A and B series tractors). Clutch lift plow models were offered through the F6xx series plows into the late 1960's (although seldom seen after the mid-50's).