A method of operating a pump/motor includes pumping working fluid into a high- pressure manifold with a first piston/cylinder assembly while the piston in the first piston/cylinder assembly is displaced from a bottom dead center position to a top dead center position, and transferring working fluid from the high-pressure manifold to the cylinder of a second piston/cylinder assembly to displace the piston of the second piston/cylinder assembly from a top dead center position to a bottom dead center position, thereby imparting torque on a cam and an output shaft, within the same complete revolution of the cam and the output shaft in which working fluid is pumped into the high-pressure manifold by the first piston/cylinder assembly.
