question about noise from frontend

[gman]

Need any ideas of what may be causing this. The frontend occasionally makes a whirling noise from what sounds like the passenger side. It don't sound good either. You can feel it up into the floor shift and transfer case lever. The odd thing is when I get out and turn the manual hubs to lock and then back, then drive it the sounds go away for a good 30 miles or so. The it comes back. It won't stop until slowing down to 45 or less. Oh yeah, the speed needs to be 45 or above for it to happen. Never does it around town. Since i don't fully understand what is happening when locking the front hubs, I'm not sure what may be causing this and why turning the hubs makes a difference. Any ideas? Thanks for any info.

[kwmech]

How about jacking up that corner of the truck and spinning the tire. Sounds like it could be a wheel bearing.