no charge hydraulic pressure john deere backhoe

[stevessuperduty]

i have a john deere 710b backhoe with no charge oil pressure to main pump at idle but ok flow at operating rpm. hydraulics all work fine if kept at a high rpm but as soon as you idle it down hydraulics begin chattering and the pump starves for oil. I have a manual but honestly it has my head spinning around trying to check 30 different check valve, relief valves...etc. Clean fluid, clean filters, clean pick up screen. Put gauges on charge oil port on pump and 0 at idle and 50-70 at higher rpms. any help would be greatly appreciated.

 

[Tx Jim]

When machine is up to operating temp check for hyd components that are hotter than the other components using a laser thermometer.