Looking for anyone with knowledge of the hitch hydraulics on a case 380ck with selectamatic controls.

Tractor has good oil level. When i remove mechanism cover from the back of the tractor it seems to have good flow. The piston bleeder screw will only have fluid come out of it when the tractor is fully revved. The hitch will not raise. I think the control valve has something stuck but would like some input before I remove it and take it apart.