Cleaning of the common drive gear (engine gears, transmission gears) will encounter a problem, that is in the cleaning process, the gear put away after the collision, not a good swing. A cleaning fluid in the gear groove to get out, dry not dry cleaning fluid but also to deposition of pollutants down, caused by the cleaning does not completely reach the cleaning effect, and some even finished cleaning out more than not before cleaning is even higher degree of pollution. In response to this dilemma, and then Kahn arrival after years of production design and development, has been successfully solve this difficult technical problems, and successfully to market.