Abstract: This invention offers advantages and alternatives over the prior art by providing a dual port hydraulic fixed displacement pump which exhibits improved efficiency by limiting the volume of discharged fluid which is subjected to the line pressure of a hydraulic system through mechanical valve control. According to the present invention, a pair of discharge ports are provided, namely a first discharge port and a second discharge port. Under all operating conditions, e.g., low and high pump speed operating conditions, the fluid flowing within the first discharge port and primary discharge passageway is exposed to the working pressure of the primary line, which represents a high pressure line. The second discharge port fluidly communicates with a secondary discharge passageway which is in selective fluid communication with a low pressure line connected to a low pressure area of the pump (e.g.