A steerable rear suspension for a tractor includes a chassis comprising a front end, a rear end, a left side and a right side; an engine mounted on the chassis; a pair of steerable front wheels coupled to the front end, left and right side of the chassis; a left rear suspension including a left rear suspension arm pivotally coupled to the chassis at a leading end of the suspension arm, and a first steerable planetary gear system mounted on a trailing end of the suspension arm; a right rear suspension including a right rear suspension arm pivotally coupled to the chassis at a leading end of the suspension arm, and a second steerable planetary gear system mounted on a trailing end at the right suspension arm; and left and right rear wheels driven by the first and second planetary gear systems.