A method for pressuring a roll pocket in a displacement assembly of a fluid device, the method comprising: providing a fluid device having a displacement assembly including: a ring defining a central bore and a plurality of roll pockets disposed about the central bore, the roll pockets including channels; a plurality of rolls disposed in the plurality of roll pockets; a rotor disposed in the central bore, wherein the ring, the plurality of rolls and the rotor define a plurality of expanding and contracting volume chambers, the rotor adapted to orbit about a central axis of the ring and to rotate in the central bore of the ring about an axis of the rotor; placing each volume chamber and channel in fluid communication with first and second ports (106, 108) during a single orbit of the rotor when the fluid device is operating below a speed threshold wherein when the volume chamber immediately before one of the roll pockets and the volume chamber immediately after that roll pocket are both in fluid communication with one of the first and second ports (106, 108), that roll pocket is in fluid communication with the other of the first and second ports (106, 108), wherein when the volume chambers that are immediately adjacent to the roll pocket are subjected to fluid at high pressure from the first port the roll pocket is subjected to fluid at low pressure from the second port, and wherein when the volume chambers that are immediately adjacent to the roll pocket are subjected to fluid at low pressure from the second port the roll pocket is subjected to fluid at high pressure from the first port. providing a fluid device having a displacement assembly including: a ring defining a central bore and a plurality of roll pockets disposed about the central bore, the roll pockets including channels; a plurality of rolls disposed in the plurality of roll pockets; a rotor disposed in the central bore, wherein the ring, the plurality of rolls and the rotor define a plurality of expanding and contracting volume chambers, the rotor adapted to orbit about a central axis of the ring and to rotate in the central bore of the ring about an axis of the rotor; a ring defining a central bore and a plurality of roll pockets disposed about the central bore, the roll pockets including channels; a plurality of rolls disposed in the plurality of roll pockets; a rotor disposed in the central bore, wherein the ring, the plurality of rolls and the rotor define a plurality of expanding and contracting volume chambers, the rotor adapted to orbit about a central axis of the ring and to rotate in the central bore of the ring about an axis of the rotor; placing each volume chamber and channel in fluid communication with first and second ports (106, 108) during a single orbit of the rotor when the fluid device is operating below a speed threshold wherein when the volume chamber immediately before one of the roll pockets and the volume chamber immediately after that roll pocket are both in fluid communication with one of the first and second ports (106, 108), that roll pocket is in fluid communication with the other of the first and second ports (106, 108), wherein when the volume chambers that are immediately adjacent to the roll pocket are subjected to fluid at high pressure from the first port the roll pocket is subjected to fluid at low pressure from the second port, and wherein when the volume chambers that are immediately adjacent to the roll pocket are subjected to fluid at low pressure from the second port the roll pocket is subjected to fluid at high pressure from the first port.