Well the following answers the transfer case question (got it off the Fritz site). Now does anyone know if the springs a different and if so in what way?
The NV241HD, an option on Ram 2500's and standard on Ram 3500's built after 1998, has a stronger case and wider drive chain to better withstand the shock of snow plow service, a PTO cover and drive gear, and an extra bearing to support the thrust to the main shaft created by a PTO adapter.
Except for dimensional differences and the PTO port on the NV241HD, all of the cases are almost identical in appearance. An identification tag is attached to the rear case of every transfer case. The tag provides the transfer case model number, assembly number, serial number, and low range ratio. The transfer case serial number also provides the date of build. For example, a serial number of 9-10-93 would represent September 10, 1993.