Hydraulic Gear Pump with Hydrostatic Shaft Bearing and Isolated Case Drain and Method of Operating a Hydraulic Gear Pump

An example gear pump includes a pump ring gear; a pump shaft; a pump pinion mounted to the pump shaft and disposed within the pump ring gear, such that external teeth of the pump pinion engage with internal teeth of the pump ring gear, wherein the pump shaft is configured to rotate the pump pinion, thereby rotating the pump ring gear engaged therewith to displace fluid from an inlet chamber to an outlet chamber; one or more cross-holes; a bushing disposed about the pump shaft; and a pocket formed about a portion of the bushing, wherein the one or more cross-holes fluidly couple the outlet chamber to the pocket, thereby causing fluid in the pocket to apply a supporting force to the pump shaft.