A liftgate load system for use with a vehicle, which includes deck sections that are movable between an in use position where the deck sections form a horizontal platform to a stowed position where the deck sections are folded a vertical arrangement. The liftgate load system also includes an adapter on the platform that is provided with a door that is movable between a closed position and an open position and backing plate that is configured to be engaged by a dock lock hook of a loading dock to limit movement of the lift system away from the loading dock. The door is configured to move from the cover position to the open position as the load platform moves from the use position to the stowed position.