Abstract: This invention relates to a shredder which has a single rotating shaft with a plurality of large and small diameter blades in a side-by-side relationship down the length of the shaft. The blades cooperate with fixed shear bars mounted on the first and the second side of the shredder. The shredder can operate in a shredding mode in a forward and a reverse direction. The shredder is driven by a hydraulic motor. The hydraulic motor has a control circuitry, which detects an overload condition in either the foward or the reverse direction. Should an overload condition be detected, the shredder will automatically reverse to eliminate the jammed condition. In normal operation, the shredder cycles for a pre-set time period in a first direction, stops, and then cycles for a second pre-set time period in a reverse direction.