We start with a factory limited slip carrier, wash it, measure everything and reassemble with 2 fresh clutches and new hardware to a higher preload than stock. Please specify the ratio you intend to use this carrier for so we can ensure you get the correct size bolt holes. When installing in a differential that was originally equipped with the M Variable carrier from the factory, different output flanges are needed. This is the limited slip only and not the complete differential. Professional installation recommended.