Ot hydraulic pump help

[idacal]

Im working on an older Italian drill rig that has a big linde pump in it powered by a turboed 6 cylinder deutz there is no information on this rig, factory doesnt have it, nobdy i can find. by sizing and seraching photos online i have narrowed it down to a linde hpr pump, load sensing pump. Guessing a 55 or 75 cc Open circuit, The control is run off of hydraulic pressure the pump is feading a danfoss pvg 120 proportional valve also pilot operated. Turning into a storie here but the pump will build about 1000 psi at idle it is 500-600 once i got it up to 1200. main pump should be at least 3000 under load Pilot pressure in the system is 400 psi what is the order for diagnosing from this point ? I have ordered a cap for the main line so i can cap it and see what the pressure does, that will bypass the relief. The valve and am going to put a gauge on the load sensing hose to see if something shows up there. See what pressures are feeding directly to the shift plates, I have been working on this most of the weekend and am needing to vent and maybe get some advice
I have drilled and tapped most of the elbows and tees for test port fitting everything that could be drilled and tapped it looks like a crazy person was working on it. Just waiting on some more bspp fittings. Of course it quit mov8ng right in front of the shop door so i eather work around it or pull planetarys to get it out out the way. Thanks for letting me vent and hoping someone here may have worked on a system like this