To add to what Bill said - use about half the "recommended" amount of Mopar limited-slip friction modifier fluid and then drive the truck to see if the clutches are grabby or not. The gear oil you use may or may not already have some additive in it so you never know until you run it some.

That said, I just changed my diff fluid (complete drain) and used 85/140 Shell Spirax and one bottle of additive and it is just right, as far as I can tell. However, your mileage may vary, void where prohibited, offer not good in Connecticut, etc.