A Pitman shaft is a column extending from the steering sector, which attaches to the Pitman arm, which moves the tie rods. Depending on the turn direction, the fluid from a pump moves a piston forward or backward. This action moves a nut, which turns the Pitman shaft and steering linkage. The movement inside the steering box causes the Pitman shaft and arm to rotate, applying leverage to the relay rod, which passes the movement to the tie rods.

 Steering Pitman Shaft and Steering sector cross shaft