Works on 2006 to current Ford F-250 F-350 4X4s having the vacuum-operated front axleCorrectly installs the seal onto the axle shaft and into the wheel knucklePrevents front hub vacuum leaks that would cause the 4WD to not engageThe OTC Ford axle shaft seal installer works on 2006 to current Ford F-250, F-350, 4X4s having the vacuum-operated front axle. Correctly installs the seal onto the axle shaft and into the wheel knuckle, preventing front hub vacuum leaks that would cause the 4WD to not engage.