Allstar ALL72155 Differential Pinion Nut for Ford 8.8" and Standard Ford 9" Differential Differential pinion nut fits Ford 8.8 inch and standard Ford 9 inch differentials. You should replace original worn or damaged pinion nuts each time a gear set is changed Pinion nuts secure the driveshaft yoke to the pinion gear Sold each Backed by a 90-day limited factory warranty