Just get under the truck and grab and wiggle your driveshafts to check the u-joints for play.

 

sometimes they will look like they dont have play when they do try using a pry bar if u need to.

 

Broken U joints make the most noise under power. It your hearing during acceleration, thats probably it. They make a clickity clack sound if you wanna get technical! If your only hearing 1 big clunk, then i suspect, broken spring, pad or loose ubolts, etc.