fits 1999 and newer GM 3/4 and 1 ton trucks with either a 10.5 or 11.5 ring gear. This sleeve goes on the yoke and the pinion seal seals against it. We have also found on some yokes you can simply remove this sleeve and used the earlier National 2286 pinion seal that will seal right on the yoke surface. This also fits 2003 and newer Dodge Ram 2500 and 3500 series trucks with either a 10.5 or 11.5 rear axle.