The Dana 44, 30 spline makes use of the 5-760x equipment that is original. They are used in the front shaft. They are normally designed for the original tire sizes and also for use moderately off road. After you upgade your jeep or you 4by4 you also have to upgrade the axle shafts as well. There several designs from the factory that are designed in such a way that they maximize on durability and on strength. They have a warranty for replacement that is ten years long. Some of the features include the fact that they are treated for heat dual that is designed to put strength where needed.