Driveline noises are very difficult to locate, particularly with a torque tube since the noise will always transmit itself up the tube. Try driving the truck in a pull/float/coast situation and see how much noise difference there is. It's possible the coast side of the ring gear is worn, or the front pinion bearing has failed. My Motor Magazine repair manual shows a ring gear backlash specification of .005" -.007".
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!