Abstract: An aggregate distributor on the rear of a truck dump box including an elongate housing extending transversely across the end of the truck and having a multiplicity of discharge ports through which the aggregate is dropped onto spinners swingably suspended from the distributor housing, a square tubular rotary shaft in the housing carrying conveying, mixing and agitating vanes which are rotationally adjustable on the shaft to cause aggregate to be propelled along the shaft in various directions, in accordance with the discharge ports that are open.