Locking Hub Squealing?

I've been noticing a noise coming from the front end of my truck. It only happens in 4 wheel drive, no matter if the hubs are locked or unlocked. I had someone else drive the truck back and forth so I could try to record a video of the noise. I did not hear the noise over the engine. A minute later I got in the truck and started plowing and heard it in the cab.

The noise is a high pitch squealing that only happens at low speeds. They also almost feel like they're "binding", but I'm not sure if that's just the 4 wheel drive or not.

Also, at high speeds, the hubs sound like they're grinding whenever I'm off the gas, A.K.A slowing down, doesn't matter if I'm coasting or braking.

So I guess I'm asking, is this just the hubs, or could something farther along in the 4 wheel drive be causing this? Thank you for any help, I just want to now before I go buying parts!