to be absolutely honest i think you are barking up the wrong tree with the relief valve. when a relief valve poops off, the system pressure will stay at the relief setting until the load is reliesed, (moving the control lever on splitter other direction should do it). then it reseats. it will not stay unseated until all oil flow stops as you describe(having to relies the remote lever then re engaging). it will be interesting to 'T' the guage in to the system before the splitter control valve, because when this prob happens, if you have pressure there it's either in the splitters valve or oil cant return to the tractor. just to go back though. i still think its the couplers, either the one's on the hoses or the female one's on the tractor. do you have another hydraulic impliment you can swap the couples out on and fit to the splitter. i may be wrong on this (definantly isn't the first time) but that would certainly be my guess if i was trying to diagnose it. bye the way, these couplers are cheap, about $15 each (AUS). is cheap peace of mind really, you said you needed to replace the hoses, maybe do it at the same time.
