Minor forms of tooth distress can happen on the gear tooth surface, but it does not always result in gear failure.
Micro-pitting may occur on areas of the tooth surface between mating teeth. This will create a light wear and a band of off-white coloring called “frosting”. A gear does not need to be replaced due to frosting, but if other signs of distress happen such as tip loading, misalignment, or severe surface irregularities, further investigation is needed.
Offset frosting occurs with lead variation in the opposite direction of mating gear teeth. A small amount of shifting and slight wear may happen until the load. Under normal operation and conditions, healing will occur and the gear life will not be lost.
Healing occurs when the balance of frosting conforms to the shape of the contact area which wears away. The rate of wear diminishes until it polishes itself out and frosting is replace with a very shiny area. No gear life is lost in the healing stage.