What is a ROCK SHAFT?

A rockshaft is by definition a shaft that does not rotate comletely around, but in a partial arc....i.e. it "rocks".

On a JD, the rockshaft is the lift shaft of the Powr-Lift or on the Powr-Trol. It rocks about a half-turn and that moves an attached bellcrank to lift the cultivators or an attached three-point hitch.

Later models used a front mounted rockshaft actuated by a hydraulic cylinder to lift front mounted equipment. It was even available on some of the early new generation tractors as an option.

Frank

Frank

On the earlier JD's, the lift unit was called a Powr-Lift, and it went all the way up or all the way down. Later, JD intriduced "Powr-Trol" which gave incremental control to the lifting action, so you could stop it anywhere during the cycle for position control.

Frank

Yes, it likely would have. The Powr-Trol came out on the '47 models and it was an instant success. I wanted to add that not only did it give incremental control of the rockshaft, but it also accomodated a remote cylinder, which was the most important feature of the Powr-Trol units. You could operate either the rockshaft or the remote, but not both at once.

Frank

I could be wrong here, because I"ve only ever seen Powr-Trol's on tractors once it became available, BUT I believe you could still order the basic Powr-Lift for less money. I could be very wrong on that, but my thinking is that is both weremutually exclusive options, that the prive dirrerence was likely so small that most opted for the Powr-Trol.

But I am guessing now.

Frank