Abstract: Method and arrangement for assuring synchronization between an engine controller and a transmission controller on a heavy vehicle with an automatic mechanical transmission with respect to maximum allowable engine torque output levels. The engine controller is programmed to automatically communicate existing programmed maximum allowable engine torque capacities to the transmission controller under all, or predetermined circumstances in order to assure synchronous performance between the engine and transmission when executing program routines that depend upon program agreement existing between the two controllers in order to properly affect desired performance in the vehicle.