Developed for NASCAR applications to keep dirt and grime from entering the axle tube and destroying critical components. These axle seals do the same thing for the front end of your Jeep. The standard plastic flanges prevent large objects from entering the axle tubes, but water, mud and grit can still pass. The axle oil seals are inboard on a Dana 30 axle so if dirt and grit does cause an oil seal leak, the axle has to be stripped and the diff has to be removed to change seals. Once these seals are installed, they are filled with grease preventing the entry of dirt and grit.