Since all pulley types are not interchangeable, Therefore, it is important to use only the type of pulley originally equipped with the vehicle. Therefore, if the vehicle requires solid pulleys, OWC or oad, pulleys of the same category must be installed. Like any other component, overrun alternator pulleys will not last forever (technicians will replace more and more pulleys). Worn pulleys can cause vibration in the belt drive system and usually cause damage to the tensioner.