Difference Between Flexplate And Flywheel What Are Flexplates? Flexplate is a large, spherical metal plate that is a crucial part of your car's transmission. Flexplate is installed in vehicles with automatic transmissions. Their primary duty is to connect the torque converter, which serves the same purpose as the clutch in an automatic car, to the engine's output. The starting motor starts the engine from a stop using the outside teeth of the flexplate, which resemble those on the flywheel.