A self-propelled filling pipe for a liquid manure spreader has a frame, an elongated pipe on the frame having a lower inlet end and an elevated outlet end, at least two wheels mounted on the frame, a caster wheel mounted on the elongated pipe proximate the lower inlet end and a fluid drive system. The fluid drive system includes a hydraulic pump, a first hydraulic circuit connecting the hydraulic pump to a plurality of hydraulic motors drivingly connected to the wheels. The fluid drive system also includes a second hydraulic circuit connecting the hydraulic pump to a hydraulic motor operatively connected to the caster wheel. A prime mover provides power to the hydraulic pump to power the hydraulic motors to rotate the caster wheel thereby steering the filling pipe and/or to drive the wheels thereby propelling the filling pipe on the ground.
