A cooling fan or use with a hydraulic pump having an input shaft in a hydrostatic transmission includes a rotatable hub having a central body portion and an axially extending peripheral surface and a plurality of blades that extend radially outward from the peripheral surface. The cooling fan also includes an attachment aperture defined by the central body portion and an integral flange that axially extends from the central body portion. The integral flange defines a guard space having an area that is less than an area defined by the peripheral surface.