Product Overview This hydraulic main control valve assembly is the original core distribution component for the hydraulic system of E336GC, E345GC, 320, 320GC, 323, 326, 330, 349, 352, and 340 excavators. It regulates the flow and pressure of hydraulic oil for the boom, arm, bucket, and travel functions. Manufactured to strict standards, it delivers stable performance and reliable sealing, making it well suited for equipment repair and replacement. Interchange Part Numbers: