The differential valve piston comprises working surfaces of at least two different diameters such that {HEAD ~ changes} in chamber pressures effect {TAIL ~ different axial forces} upon the piston 
effect
The differential valve piston comprises working surfaces of at least two different diameters such that { HEAD ~ changes } in chamber pressures effect { TAIL ~ different axial forces } upon the piston
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH