Rear end could very well be an AAM ( American Axle & Manufacturing )
The AAM 10.5" axle, also known as the Chrysler 10.5" is found in 2500 and 3500 3rd Generation Hemi V8 Ram trucks as well as some earlier diesel and V10 Ram trucks. The '05 and newer Ram Power Wagon also comes with this axle equipped with a locking differential.
but then again, it may be a Dana 70
the easy way to tell is to look at the shape of the rear differential cover