Broken rear end?

[gtman220]

I need some help understanding this drive system. I have a 2004 XC90 AWD (2.5 liter turbo). The front CV joint on my drive shaft let go. All six bolts are gone, grease is everywhere, etc. As I'm underneath the car trying to figure this mess out, I put my hand on the driveshaft and it spins freely while still engaged to the rear end. So...is my rear end broke or is there some kind of pressure engagement system inside the rear end? The last time I was in the snow, the AWD worked as normal. What do you guys think?