hey there... there is only one hyd pump in our 2310s. what splines are you talking about? splines on the pump? if it moves back and forth then the pump is working. does power steering work? how about front end loader? how about 3pt hitch? how about backhoe? I had a problem where my hoe stopped working but I think everything else worked. when trying to move the hoe I could hear teh main pressure relief valve squeel... turned out the 3pt hitch raise/lower lever had bent and was rubbing (hard) against the fender where the lever protrudes through the fender. Once I carefully bent the lever straight, I noticed that when I moved the lever all they way to the "up" position (all the way back if I remember correctly) the lever would stay there until the hitch raised to the full up position, then it pushed on a spring connected to the hand lever which moved the hand lever out of the full up position, allowing the hyd pump to stop pushing on the 3pt hitch mechanism. When bent, there was too much lever/fender friction for the spring to do its job and the the 3pt hitch hyd circuit was always pushing... and it was stealing hyd pressure from the hoe circuit.
now... other things to check - make sure all 3 quick disconnects are freed up that go to the hoe... there is one of them in particular that if not completely connected and blocked, will mess up a whole bunch of stuff... search for my other post where I describe my trouble shooting steps from a year ago...
Let us know how you make out.