You need to crawl under your truck with a flash light to verify that all 3 of the front u-joints have grease fittings. If they don't that shaft must be rebuilt or replaced, even if it is not causing your sound, because when it fails, and most of them do, it will destroy your tranny also.

 

These senior members and on up know alot more than I do, but I can tell you that removing the (front) driveshaft is as simple as removing eight nuts.... slide it out, and take it to a driveshaft shop. Replacing the U Joints looks really hard if you don't have the right equipment (ie, a large press with the right fittings). I have seen it done on YouTube (using a vice and a socket and a big hammer), and decided to go to a shop. The U joints are cheap and if it is off the vehicle, the labor is too.