An improved frame for a drawn agricultural implement, such as a planter, includes a central main frame which is extensible. As the main frame extends, the wing sections fold forwardly. When the wing sections fold to a predetermined position, positioning links act to pull the main wheel set, which is mounted to a carriage and supports the rear of the central main frame, forwardly so that the down load on the hitch is reduced. Conversely, during the unfold cycle, after the wing sections have unfolded to a predetermined position, as unfolding continues, the positioning links urge the carriage and main wheel set toward the rear of the main frame to the field use position. A hydraulic circuit for folding, unfolding and preparing the implement for transport is also disclosed.