A surface pump assembly having a thrust chamber with a telescoping shaft. In some embodiments, the surface pump assembly has a pump with a pump shaft, a thrust chamber with a telescoping shaft extending therein, the telescoping shaft extendable to engage the pump shaft and retractable to disengage the pump shaft, and a motor coupled to the telescoping shaft and operable to rotate the telescoping shaft. In some embodiments, the telescoping shaft has a rotatable shaft member, an adjusting nut threadably disposed thereabout, wherein the adjusting nut is moveable axially relative to the shaft member by rotation, and a first sleeve translatably disposed about the shaft member.