This has been an issue with my tractor id say for a couple years now, i just havent had anytime to try to chase this down. I really havent used the 3 point much, primarily my front end loader. however i just aquired a 50" buhler snowblower recently and well i cant use it now! From a cold start about mid RPM to wide open the 3 point with weight works fine, however once is seems the fluid starts warming up thats when it barely will lift anymore to the point it just doesnt lift at all. you can hear it trying but just nothing. I replaced the piston seal a couple years ago thinking that was the issue, but it never resolved. i pulled the priority and pressure relief valve the other day to check them and all looked ok. i am waiting for a metric adapter to get here to check the pressure by the piston per shop manual. however i checked the pressure coming into my FEL valve the other day and i got around 2100 which seems high but idk how accurate that guage is! To me it seems the pump and valving is fine because my power steering and FEL always are working fine. Only thing i can come up with is when the fluid starts thinning out, it just seeps past that cylinder seal. any other thoughts on this? thanks