A mechanical system used for transferring power from a truck engine to another component, such as a pump, located elsewhere on the vehicle.

In some liquid-fuel delivery operations, it is common practice to pump fuel from the truck to storage tanks. If the pump used for this purpose is permanently mounted on the truck itself, there must be some system for delivering power to the pump. The power takeoff (PTO) serves this function. It consists of a series of gears and a shaft, connected to the truck engine on one end and the pump on the other.

With the engine running, the truck operator engages the PTO. The shaft begins to rotate and its movement, in turn, operates the pump.