An agricultural combine such as used in the harvesting of crops includes oscillating or fixed forward tandem drive wheels which are coupled to the combine's support frame, or undercarriage, to provide a smooth ride over rough fields and a more uniform crop cutting height above the soil. The combine also includes a body typically housing a diesel engine, operator controls such as in an enclosed cab, a grain and residue separating system, a grain storage bin, and an auger of off-loading the harvested grain. The combine body, which also typically has an array of row crop heads disposed on a forward portion thereof, is disposed on and coupled to the support frame in a slidable manner permitting the body to move forward to distribute the weight primarily over the tandem drive wheels for improved traction for operating in muddy fields and to accommodate larger grain loads. The combine body may also be slid rearward on the support frame to distribute sufficient weight over the aft steerable wheels to facilitate turning of the combine such as at the end of a field. The tandem wheel arrangement is also adapted to accommodate a drive track arrangement for even greater traction, with steering provided by an independent track drive or braking arrangement.