What engine?
The front is the Dodge only psuedo Dana 60 (ie good for ****) and the rear would be a D60 if it was a V8, D70 if it was a V10 or Cummins with an auto, and the 5 speed stick Cummins trucks got the D80.
I'm 90% sure the V10 and Cummins parts are right. They used all three rear axles in those trucks but the engine arrangement gets confusing.