Ensure your semi is Ready for the Road Ahead with rapid power from a cold engine, with the Delco-Remy 39MT 12V 12-Tooth Starter Motor with OCP. Once an ignition button is pressed or key is turned, this replacement starter works with the battery to activate the engine flywheel. Built with durable components to keep each starter at its best for vast periods of time. FleetPride is your First Click in Heavy Duty .