Abstract: An attachment for a vehicle suspension system of a type having a frame, a pair of leaf springs attached at the ends thereof to each side of the frame and operatively attached centrally thereof to the rear axle housing. An abutment structure is attached to the frame on each side thereof just above the leaf springs on each side of the frame. These abutment structures are positioned generally between the rear axle and the rear end of the leaf springs for contacting an upper portion of the respective leaf springs under heavy load conditions to effectively shorten the operative length of the leaf springs automatically whereby the load will be effectively redistributed from rear to front upon engagement of the abutment structures with the top of the leaf springs. Structure is also provided for vertically adjusting the position of the abutment structures with respect to the leaf springs.