I'm guessing you know the difference between an open differential vs. a traction-aided or locking differential. If not, here's a wikipedia link to a decent overall description of the types available. It sounds like you have the more conventional open differential, and perhaps you want a limited slip, traction-aided, or whatever other types and versions are available. From what I've seen on the forum and looking at some aftermarket diff sites, Dodge may be the only one offering a limited slip diff for the later pickups. While it's only a $325 option at time of purchase, it's going to be fairly expensive to get it done after purchase. Still, it's a doable deal.
http://en.wikipedia.org/wiki/Differential_(mechanical_device)
http://en.wikipedia.org/wiki/Differential_(mechanical_device)
