Ford Racing M420988331 8.8" 3.31 Ring and Pinion OEM quality: The superior surface finish, hardening, and manufacturing consistency provide the strongest and quietest 8.8" gears in the market Includes Ford pinion nut and Ford crush sleeve Made in the United States at Ford's Sterling Axle Plant No one does 8.8" gears better than Ford Racing...stronger and quieter! Fits any Ford 8.8" rear end until 2014. Does not fit 2015+