Check your front hubs for movement and the ball joints at the sametime. It is unlikely, but possible that the front CV's have gone bad. Best option is to replace with new on any vehicle IMO. One way to isolate the sound is by placing truck on jackstands (on level ground ofcourse) or a two post lift and engaging 4WD and finding where the sound is likely coming from. Be careful with the throttle as the truck can still rock front to back if on jackstands!
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