Abstract: A self-dumping self-retracting cargo bin adapted for installation in a conventional pickup truck without need for tools or alteration of the truck. The bin has front and rear roller means for supporting the bin on a loading dock or the like when not in a truck. When mounted in a truck, the rear end of the bin is supported on fulcrum rollers carried by a latching sub-assembly extending crosswise of the truck body with latch means positively embracing the truck's rear stake sockets. The bin is self-dumping when its rear doors are unlocked and it is released from its travel mode merely by starting the truck forward abruptly. Energy stored in heavy duty retraction springs during the dumping cycle is effective to restore the bin toward its travel mode.