Bill, that's kind of a loaded question, because even between gasser and diesel on the DLD/DHD, many of the internals are the same.
Some of the most radical differences were around 1996, when the large output DHDs started showing up.
Aside from that, many of the DLD/DHDs I have been into have only differed from the input bearing, input length and input size.
SOME will have a longer input for a given spline count.
For example, there are 23 spline inputs with a longer stick out and some with a shorter.
IIRC, 1994-up 5 speed gasser NP241s require a slightly longer input to fully engage.
For the 241D, as far as I have been into one, I can't see any real differences other than the obvious left-to-right case differences, and, of course, the extension housing design.
They use a lot of the same, or similar pieces, like range forks, some hubs and slider assemblies.
I have NP241D here that I may still put a 29 spline input into, but I need to crack it open to see if it uses the wide or narrow input bearing design, so I can order the input and any other dumb stuff that "may" be different.
The problem with the Dodge 241s is that New Process (New Venture) made so many running changes, sometimes purely dependent on parts AVAILABILITY, meaning they could throw a wide input and bearing in an automatic DLD, just because they were out of narrow bearing inputs at that time.
But I need not delve much further into how auto manufactures can go off the beaten path.
oke:
One thing I will say, the NP241 as a whole is an extremely simple t-case and, for it's weight and size
Given proper fluid levels, it's a fairly hardy one, too.
In re-reading this, yeah, there is a crapload of differences!
Mark.