Stock/OEM drivelines come with the standard non greasable u-joints that can't take the abuse or stay lubricated to be efficient or have longevity. Replace your stock u-joints with our Upgraded greasable u-joints with the best internals, needle bearings, & grease that money can buy. With extreme off-road conditons: mud, water, sand etc. having a greasable u-joint gives you the ability to keep your driveline components lubricated at all times.