truck in signature is making a noise. i'm overseas but my oldest is describing it as a rubbing sound, like oversized tires that rub. Tires don't rub, they've been on now for almost 55k. pulled the tires and nothing in the brakes and the pads are okay. got it up to about 20 and when he shifts to neutral it goes away. when he goes back in gear the noise comes back. any ideas? can the trans/torque conv/transfer case make a noise like a rubbing sound? seems like it's in that area if the noise goes away when in neutral and come back when back in gear. he also checked the u-joints and they appear okay. no fluid leaks.

 

Kid took it to the a mech that i've used for years and he thinks it may be the u-joints. still hasn't put it up on the rack to look though. anyone ever had them make a noise when they went bad? any recommendations as to replacement types if that is the case?