If using an aluminum piston in forward, there will be 2 wave plates. The pressure plate will be thinner. So stack up with aluminum piston will be wave, friction, steel, friction, steel, friction, steel, friction, wave, pressure plate. If using steel piston, the pressure plate is thicker, stack up is wave, friction, steel, friction, steel, friction, steel, friction, pressure plate. ATSG only shows the newer design with the aluminum piston. Leave at least one wave installed.