A flexplate or flex plate is a metal disk that connects the output from an engine to the input of a torque converter in a car equipped with an automatic transmission.
[1] It takes the place of the flywheel found in a conventional manual transmission setup.
[2] Flexplates are generally much thinner and lighter than flywheels not only because of the required flexibility, but also due to the smoother coupling action of the torque converter[3] and the elimination of the clutch surface.
[4] Like a flywheel, a flexplate normally handles coupling to the starter motor via gear teeth cut along its outer edge.
[citation needed] Flexplates come in many forms, but are usually either stamped steel (for road cars), a machined two-piece billet (for race cars), or a machined one-piece billet (for high-performance drag racers).