An air driven double diaphragm pump has two opposed pumping cavities (16, 18) with diaphragms (20, 22) extending across the cavities. An actuator housing (10) includes a control valve assembly (52) having a control valve (76) to direct pressurized air to one or the other of the dual pumping cavities (16, 18) and two relief valves (116) which cooperate with the pump shaft position to release air from one end or the other of the control valve (76) for the shifting thereof. Shuttle valve elements (160) are positioned between the control valve (76) and the pumping chambers (16, 18). The shuttle valve elements are slidably positioned within the valve (162) to move between extreme positions under the pressures within the input and the pumping cavity. In one extreme position, the pumping cavity is in communication with an exhaust (168) having a tapered passage. In the other, the exhaust is cut off and pressurized air is able to pass through a one-way valve (178, 182) in a passageway (174) through the shuttle valve (160) element to charge the pumping chamber.