We created our Dana 60 Super Duty unit bearing grease zerk adapter to install in the same location as the ABS sensor on Ford 05-up Superduty axles. In stock form no provision is provided to add grease to your unit bearings. By adding this adapter you will be able to add grease to your unit bearings and extend the life of the bearings. If you are swapping an axle into something else and will not be using the ABS sensors this is also a fantastic solution to plug the hole. If you will be using the ABS sensors after your swap, or even on a stock application this can be used to add grease for periodic maintenance. Installation is as simple as removing the ABS sensor and installing this in its place. These are sold individually and all required installation hardware is included.