05 Tahoe Z71 tranny or bearing noise

[jonbert]

2005 Tahoe Z71: I've noticed a noise from under the truck when I use the Auto 4WD button and decelerate or coast to a stop. (I have 4 buttons: Auto 4WD, 2WD, 4HI, 4L) It resembles the noise or hum of knobby tires on a smooth paved surface. Putting it back to 2WD eliminates the noise. Any ideas? Thanks in advance.

 

[Eng1Driver]

When you're in 4wd some noise is normal because the transfer case will make a hum/whine noise while engaged.