Abstract: A torque transfer coupling includes a shaft and a first second set of hydraulic devices. Each hydraulic device of the first set of hydraulic devices has a first end operably connected to a first end of the shaft, wherein the hydraulic devices of the first set of hydraulic devices are disposed about an axis of the shaft. Each hydraulic device of the second set of hydraulic devices has a first end operably connected to a second end of the shaft, and wherein the hydraulic devices of the second set of hydraulic devices are disposed about the axis of the shaft. Each hydraulic device can include a piston and cylinder assembly wherein extension and retraction of each piston of each hydraulic device is generally tangential to a portion of a circle encircling the shaft.