Abstract: A grease pump including a gerotor pump. The grease pump includes a head, a source of grease, and a discharge conduit. The head has bores defining an inlet passage and an outlet passage, and additional bores in communication with the inlet passage that lead to an air vent valve and a grease fitting. The gerotor pump is disposed in the head and is caused to rotate by an external, separate rotary power tool. By design, the gerotor pump will stop pumping grease when air accumulates in the outlet passage, and air vent valves in fluid communication with the inlet passage and outlet passage may be used to relieve air from the device.