Well, finally got a floor jack and some time to check out the noise. I know to check for wobble in the tire but is there anything else that I should be looking for?

you can move the tire 12 to 6 and if it moves the bearing is bad. mostly just going to be the noise. ive done probably 3 dozen bearings like that only two had any play, one was a bonnie he had drove for like 3 months with the noise and the other a ram that the wheel fell off, but dodge has a different internal design i think. ive never seen a gm do that.

do I have to replace the whole bearing assembly or just the bearing and repack it with grease

its a hub assembly.

The bearing is the whole assembly. Here is a pic.
2008 Chevy Silverado 1500 ALL (4WD) - TC0490601 Brake Caliper

I have to replace the whole hub assembly
? should I do it myself or have somebody do it? how much we talking to do this?

Well if you do it the part is 165 for a 1 yr warranty or 246 for a 3 yr warranty at autozone. And 260 from the gm site. If you do it you have to take the brake caliper and rotor off. Then their is 3 bolts that thread into the wheel bearing from the back. You have the sensor to unplug. Then their the axle nut thats a big nut. You take that off then have to tap the axle loose by hitting it back and then have to hit the wheel bearing usually pretty hard to free it from the spindle. If you have the socket big enough for the axle nut and a impact is almost a must to remove it. If not youll need a big pipe and have to remove that before you take anything else apart so you can stick something into the rotor to keep it from turning.

they are going to charge quite a bit. its alot of labor, but if you are pretty handy it doesnt seem difficult. you can get the axle hub socket from a parts store rent for free deal. impact gun will make it much easier. shouldnt come apart too bad being a 08, some times you need a punch and a bfh to get the unit out of the spindle. parts geek or rock auto have decent prices on the hub

you can do the axle nut with a bar, before you jack up the vecle and take the wheel off

Can you call me please? -------------. Names patrick