Abstract: A mechanical cargo shifter is used in cooperation with a mechanical cargo handler, where cargo is organized into cargo positions arranged as rows and columns, and where the cargo handler and cargo are supported upon a platform attached to a truck or trailer. The cargo shifter includes a guide, and a base movable to follow the guide along the platform. The base supports the cargo handler which is fixed to the base. A carriage is attached to the base to be movable in an opposite direction to that of the base. A shifter bar reversibly extends from the carriage to a position adjacent a cargo position. When the carriage is moved, cargo is shifted to create either a cleared position or a loaded position next to the cargo loader, as needed. When a row is fully loaded or emptied, the base moves to the next row area.