2005 Sierra Denali- Front end/transfer case noise?

[dginas]

I have a 2005 Sierra Denali with 60k. It has a winding noise(like off road tires on asphalt) that has gotten worse for the last 10k miles. the faster i drive the louder it gets and doesnt stop until the truck stops. Sounds like it is coming from the front of the truck and since it is allwheeldrive i am worried it is going to be expensive to fix. Has anyone else had this problem? Any hints as to what it could be and how to diagnos? There is no slippage, the noise does not change when i accelerate or turn and there is no wobble in the wheels. Thanks for the help.

[calvinator03]

It sounds like you need carrier bearings in the front diff. Ive seen a bunch of these do this. I think gm got a bad rash of bearings.