4wd High Noise?

[a42887]

So I put my truck into 4HI for the first time, and while driving at any speed on pavement that is snow covered (or really anywhere), there is what sounds like a hum or slight grind coming from the front of the truck. I have a 2010 Sierra with the manual transfer case. Is this normal?

[uchi]

And 4wd I've ever owned made a hum while in 4 hi. I'd imagine this would be the same.

[uchi]

Supposed to say any not and. Stupid touch screen phone.