Abstract: A reinforcement member for a cylinder in a vehicle automatic transmission is in the form of a plate having a top surface generally parallel to a bottom surface. An edge surface circumscribes and is generally perpendicular to the top and bottom surfaces. The top and bottom surfaces have two opposed concentric arcuate sides and two opposed rounded ends. The radius of the first arcuate side is smaller than the radius of the second arcuate side. Two fastener holes extend from the top surface to the bottom surface near each rounded end. An apply hole for the flow of hydraulic fluid extends frown the top surface to the bottom surface between the fastener holes.