an apparatus and method for finishing the mating surfaces of a gear set or gear train including at least a first and second rotatably connected gear element in dynamic , lubricated contact . a hardness differential is employed between mating gear surfaces to balance surface damage imparted by friction and plastic deformation . the invention also includes subjecting the mating surfaces to a polishing process , preferably isotropic chemical finishing , to shape the surface asperity profile , thereby reducing accumulative damage due to friction and plastic deformation .