A planetary gearset includes a sun gear member having a sun gear body made
of a steel material and an outer periphery with a plurality of teeth
formed thereon. Each of the sun gear teeth has at least one mating surface
for engaging mating surfaces on complementary teeth on at least one planet
gear. A fatigue-resistant coating is applied to the mating surfaces of the
sun gear teeth. The coating is harder and more abrasive than the mating
surfaces of the planet gear teeth.
