Working on a 320 skid steer 15 years old ,it has a heavy violent hydraulic chatter on hoist cylinder lower and seems to be restricted on hoist cylinder up . Noticed bucket curl/dump have also the same issue just no chattering . In playing around i notice pulling the pressure release cable allows operation to return to normal . Does anyone know what could cause obstruction to flow it seems from MCV to tank on return circuit or am i on wrong track
The port lock solenoid on the side of the control valve might be an issue. That solenoid supplies pressure to that release valve to open it. You are just opening it manually with the cable.
Thanks for the information ,I tested port lock solenoid valve and it was faulty. I ordered 1 and replaced it and issue was repaired