So after about 2 hours of heavy field mowing my hydro lines get real hot and after about 4 hours of operation thers a noise under seat, even when impliment is lowered it sounds like hydro system is straining as if ther was still a load on it. Also it will not lift implament up unless I have the rpm"s above 1000 but only when its hot. When cold it lifts fine at idle. I have checked orfice screen and suction screen and they are both clean. I had hydro pump apart a year ago to replace gaskets cause I had engine oil in hydro system and the pump looked ok to me . Any help would be much apriciated thanks in advance