'01 2500 Dodge/Cummins 5.9 235 hp/460 torque 47RE tranny. Bought the truck new and put 85+k miles of trouble free service pulling a 11.2k 5th wheel rv trailer......a 16k GN triaxle stock trailer and other size flatbed trailers I use. Boy....was the old 2nd gen 24v 5.9 noisy.
I sold it and bought the new quiet 3rd gen '03 2500 Dodge/Cummins 5.9 HO 3.73 gears NV5600 6 speed manual with 305 hp/555 torque in my sig. With over 300k miles its still ready for any weight coast to coast.
It easily tows all of the trailers above.
The '03 and '04 Dodge trucks use the same 5.9 305/555 HO engine.
The '03.5 and '04 had the new 48RE auto tranny which was a big upgrade over the 47RE auto tranny.
If you haven't operated a 5 or 6 speed HD manual tranny in these trucks I would drive one first as they aren't for everyone.