Unidentifiable squeaking sound coming from rear end

[JDude]

I started noticing this noise a few days ago and its slowly starting to get worse (Video included). My truck is a 2008 1500 5.7 4wd. I took the driver side wheel off and looked around and I couldn’t find anything. Maybe someone can help or give some suggestions?
Thanks.

 

[fastf]

Have you thought about getting someone bouncing on the rear bumper and you look and listen under your truck?

 

[SYKRAMMAN]

Wheel bearings. Don’t let them go too long, otherwise you will oval out your axel housing and they are 900$ from junkyard.

 

[JohnnyMac]

Does it happen only when accelerating, decelerating, coasting, or all the time? I had a U-joint once that made a similar noise, but only while coasting. When I applied power, or was slowing down on compression, it got quiet. But I also think SYKRAMMAN is probably on to something and you should check out the wheel bearings.