Front differential noise

Have you checked the outboard axle joints?

Shaking these joints can be decieving. What you're looking for is rotational movement. If there any slop at all between the 2 halves of the joint as you turn the wheel, the joint is probably bad.

Obviously, I'm not sure what you mean by "a little loose", but as a rule, an inner (inboard) joint won't make any noise unless it's "really" shot. Inner's don't flex as much as the outboard units. You may want to check "slop" in the front differential. The input shaft should have only 2 or 3 drgrees of freeplay before making contact with the ring gear. Turning the axle shafts, they should have have almost no slack.

The picture I attached previously is of the "inner" joint. They are basically the same except the outer is a male spline, the inner is female. For the inner "female" part of the shaft to move up and down a little is not uncommon, as long as it moves so much that the seal is leaking.
Question; Do you, perchance, have a lift kit in this truck? Is the truck used quite a bit "off road"?

Ok, I think we're on the same page. There were 2 different front differentials used in you truck. One had a "slip clutch" system, the had a mechanical lock controlled by a vacuum actuator. Which front end do you have and which bearing are you looking at. Just give me the #, and we can go from there. I'm being cautious here 'cause I don't want to give you the wrong info.

Yep, the differentials can make a noise like a bearing is going out, there is full and part time systems can you control when your car goes into 4wd? If so you have the part time system. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.