Well first of all get that screen cleaned and flush it out. Add some clean oil unscrew an end off of a hydraulic line and see if you have flow. If you do get a pressure gauge 3000 PSI capacity and see if you have any pressure. That pump may have been caviated and it is history. Remember there are two distinct series of those tractors and also 2 different hydraulic pumps. I have to wait until the eye gets a little better but I think you have the later series tractor.