COMPONENT OPERATION / Signal Control Valve SHUTTLE VALVE The shuttle valve selects pilot pressure used to per- form each operation and routes pilot pressure to the corresponding control valves and/or control spools. The spools corresponding to each operation are as follows: Swing Parking Brake Release Spool Boom Raise { Boom Lower { Arm Roll-Out { Arm Roll-In { Bucket Roll-In { Bucket Roll-Out { Right Swing { Left Swing { Right Travel Left Travel Auxiliary { T3-6-6 Arm Flow Rate Control Valve Control Spool Flow Combiner Valve Control Spool { { {