A phaser for controlling the timing between a camshaft and a timing gear having a rotor with at least one vane and a stator with at least one recess the phaser allowing limited rotational movement of the rotor with respect to the stator. The vane divides the recess into first and second pockets, wherein the introduction of a fluid into the first pocket causes the rotor to move in a first rotational direction relative to the stator, and in that the introduction of a fluid in the second pocket causes the rotor to move in the opposite rotational direction. A control ring is provided for selectively opening and closing a fluid connection between the pockets to allow fluid to flow between the pockets using the pressure difference of the fluid in each of the pockets to transport the fluid from the one to the other pocket.