This front axle oil seal retains lubricating fluid inside the axle housing and prevents contamination from entering the rotating assembly. It sits at the wheel-end or pinion interface, where the shaft passes through the housing. A worn seal allows gear oil to escape, which reduces lubrication to the bearings and differential components, and can draw dirt into the hub. Corteco manufactures this seal to match the original housing bore and shaft contact surface, so the lip rides on the correct wear track without requiring a sleeve or adapter. Replace the seal whenever the axle shaft or hub is removed, and inspect the contact surface for scoring before installation.