Abstract: Load retention devices for material handling vehicles are inadequate in maintaining load position and inflexible in load transfer operations. First and second blocking devices having elevationally movable gates are mounted adjacent opposite sides of the frame of a material handling vehicle and adjacent a load supporting apparatus. The first and second gates are guided for elevational movement between a first position above the load supporting apparatus at which a load on the load supporting apparatus is blocked from side passing movement and a second position beneath the load supporting apparatus at which the load is free to pass the first and second sides. A first power device is provided for selectively moving the first gate member between the first and second elevational positions and a second power device is provided for selectively moving the second gate between the first and second positions.