Go to this site and print the jic identification sheet off
https://www.surpluscenter.com/Tech-Help/Hydraulics/Thread-Identification/JIC/You have either jic 6 or 8 most likely going into the valve. Whichever it is go back on their site and get a tee with fittings to hook to a 3000 psi gauge. Hook that up and see what your pressures are doing at idle,driving, loading etc. this will help us know where to look for the issue