Abstract: An apparatus is provided for reducing the temperature of an axle assembly by moving the lubricating fluid from the hotter to the cooler portions of the axle assembly. The axle assembly has an axle housing with a central portion and opposing legs extending from the central portion. A pair of shafts is disposed within the legs. Each of the shafts has an outer surface and first and second opposing ends, with at least a portion of the first ends located within the central portion. A differential gear set is arranged within the central portion and engages the first ends. To cool the lubricant, at least one helical protrusion extends from the outer surface of the shafts at a location adjacent to the differential assembly. The helical protrusions move the lubricating fluid from the first end in the hot central portion of the axle housing to the cooler second end at the extremity of the axle.