Abstract: A hydraulic platform lift for use on trucks and truck trailers has two hydraulic cylinders, one on each side of a door. The cylinders are phasing cylinders in that one cylinder is larger than the other cylinder by a specific ratio. The cross-sectional area of the fluid in the rod end of the larger cylinder minus the area of the rod is equal to the cross-sectional area of the smaller cylinder. A connecting line interconnects the rod end of the large cylinder with the cap end of the small cylinder. Hydraulic fluid can be directed by a controller into the cap end of the large cylinder or the rod end of the small cylinder. For upward movement, hydraulic fluid is forced into the rod end of the small cylinder. This in turn forces hydraulic fluid through the connecting line into the rod end of the large cylinder, thereby raising both pistons.