TM 9-2320-366-34-1 2-1095 FOUR WAY CONTROL VALVE ASSEMBLY FLOW TEST NOTE If hoist suddenly loses power, when not overloaded, or fails to shut down, when overloaded, relief valve RV1 is faulty. Clean or replace RV1. To test in hoist-down position substitute port B for port A, in steps (2), (3), (14) and (15) and in step (8) operate hoist-down. (10)  Stow MHC (TM 9-2320-366-10-1). (11)  Position MHC power to OFF (TM         9-2320-366-10-1). (12)  Position PTO switch to off (TM         9-2320-366-10-1). (13)  Shut down engine (TM 9-2320-366-10-1). (14)  Disconnect hydraulic tester, hose and adapters         from port A and hose. (15)  Connect hose to port A. WARNING Wear approved eye protection when performing pressure checks. Failure to comply may result in oil getting into eyes.  If oil contacts eyes, seek medical attention immediately. Drop hydraulic pressure to zero before disconnecting any hydraulic hose, tube, or fitting. Failure to comply may result in injury to personnel. Fuel and oil are slippery and can cause falls. Wipe up spilled fuel or oil with rags.  Failure to comply may result in injury to personnel. If hoist will only work in hoist down position, perform visual inspection of winch-up lockout valve. Replace damaged winch-up lockout valve. If necessary, perform electrical system troubleshooting (TM 9-2320-366-20-2).   (1)  Place drain pan under vehicle.   (2)  Disconnect hose from port A of hoist control         valve.   (3)  Connect hydraulic tester between hose and         port A with test hoses and adapters.   (4)  Start engine (TM 9-2320-366-10-1).   (5)  Position PTO switch to on (TM         9-2320-366-10-1).   (6)  Increase engine RPM to 1250-1450 RPM (TM         9-2320-366-10-1).   (7)  Position MHC power switch to ON (TM         9-2320-366-10-1).   (8)  Operate MHC to raise a moderate load with         hoist (TM 9-2320-366-10-1).   (9)  Observe reading of about 9 gpm (34 lpm). If         flow is low, replace control valve in four way         (upper) control valve assembly.