JD 2003 4510 faulty Hydraulic’s

[Handlebar]

I want to make a hydraulic pressure tester to test the pressure going to my 460 loader. The fittings are Parker 60 series. The male end is labeled H3-63-T8. I do not know the thread size of this fitting that the pressure gauge will screw into. Or will I need an adapter between the fitting and the gauge. Should have 2500 psi at the gauge. My problem is very erratic lifting and dumping of the bucket or no lifting at all. Changed hydraulic oil and filters and screen last October. Put tractor up until May when this problem surfaced. Had back surgery May 20th and just now getting back to this problem.