Product Details: Outfit your semi truck to be Ready for the Road Ahead™ with a seamless transfer of engine power, with the Dayco 57" Heavy Duty High Performance Transmission V-Belt. By utilizing a synthetic rubber, this replacement belt is able to transfer power from the engine to the transmission to enable gear changing and other key functions. Built with increased flexibility to optimize airflow for long-term cooling and reliability. FleetPride is your First Click in Heavy Duty®.