All carburized gearing distorts due to the quenching operation after carburizing to get the required core strength. Distortion, in layman terms, is a twisting of the gearing, especially thin sectioned gearing like the ring gear or intermediate sleeve. If the distortion is not corrected, the gearing will fail prematurely from worm tracking or spalling. Distortion should be corrected. There are three methods - lapping, skiving and grinding. Although lapping and skiving may be done to increase gear life, it is no comparison to a gear set that has been ground. Ask your supplier for applications lists and reference contacts when considering different gearing options.