A variable displacement hydraulic/pump motor has a yoke with a pair of
shafts aligned to define a yoke pivot axis and connected to a valve plate
therebetween having intake and discharge apertures. A rotatable cylinder
barrel has piston cylinders open at one end to receive a piston head and
opening through fluid ports at another end, flush against the valve plate
surface. A drive block is mounted on an input/output shaft for rotation
about a central axis of rotation inclined at an angle relative to the
longitudinal axis of the cylinder barrel which may be changed by a drive
engaging the yoke at a point near its pivot axis. Loads on bushings
supporting the yoke shafts are reduced by providing radially extending
fluid ports in the shafts and in communication with the intake and
discharge apertures of the valve plate.