Abstract: A hopper assembly for a ready mixed concrete truck having a material off loading position and a material on loading position. The hopper assembly includes a main chute portion and a movable portion movable between an open position for off loading and a closed position for on loading. The movable portion directs material directly into an opening of a mixing drum providing for the rapid on loading from an overhead delivery apparatus when in the closed position. When the movable portion is in the open position or off loading position a passage area between the hopper assembly and the mixing drum is increased thereby eliminating a restricted area to provide for the effective dispensing of high viscosity material such as low slump concrete.