I run a Detroit Locker in my 89 Dakota daily driver with 4.10 gears, and I gotta agree with most of these guys, I wouldn't recommend any locker for regular snow driving. It's great for traction/drag racing and towing but it could get you into serious trouble in the snow - I definitely wouldn't chance it on a family car.
I love mine, but it hops and chirps a lot while making sharp turns at low speeds. People in the neighborhood love it

I have the sof-lock model, and it's generally silent, but every once in a while, out of nowhere it does some pretty violent locking/unlocking, jarring the whole truck and really freaking out the passengers. I've had it for about 2 years now and don't get me wrong, it's great and I wouldn't trade it, but I wouldn't wanna drive it in the snow either. However, I would imagine that a Durango has a lot more weight in the rear and would not be quite as ill tempered as my old Dakota. I also forget sometimes that not everyone else drives like a total maniac...
Now correct me if I'm wrong, but I think differentiation during turning is the basic Idea behind any auto locking differential. The problem is, if your rear end doesn't have enough weight, it won't unlock on sharp turns, especially at lower speeds (and I would imagine at high speeds on snow). This has been a problem for me a couple of times in the rain (you know, doing a 180 while turning a corner in traffic). I've never had a problem with it at higher speeds, other than the usual goosing it on a curve and the truck lunging to the opposite side of whichever wheel has traction. That can be a bit scary but you get used to it...
I would keep it safe with the LSD if I was you (Limited Slip Differential), but I'm no "expert". Good Luck whatever you do!