Some embodiments of a clutch system may drive an output portion to rotate at a first rotational speed when the clutch surfaces are engaged and to rotate at a second rotational speed when the clutch surfaces are shifted to a disengaged position. The viscous two-speed clutch system may employ a viscous drive system that causes the output portion to rotate even when the clutch surfaces are disengaged. In such circumstances, the cooling fan can be driven to rotate at a first rotation speed due to interconnection with a drive source and to rotate at a second rotational speed even when the clutch surfaces are disengaged. Thus, the clutch system facilitates the flow of cooling air both when the vehicle cooling system activates the fan (e.g. by causing the clutch surface to engage) and when the vehicle cooling system deactivates the fan (e.g. by causing the clutch surfaces to disengage).