I have a 1997 3.9l 4x4 Dodge Dakota, What is the difference (if any) between transfer cases 231D and NP231. I recently have noticed fluid leaking from my transfer case and ordered a seal and gasket kit for it. Just wondering if i ordered the wrong one the tag on my transfer case reads 231D but the parts kit i ordered was for "NP231", but says it fits this year model....Is this true? Any help is appreciated!!!!

 

NP is the manufacturer, new process. 231 is the model number, D denotes dodge. So far as I know, seals and gaskets are the same, regardless of what it got bolted into. Diffeences were in input shafts, output shafts, and spline counts. Probably how it was clocked relative to the trans as well. The kit you got, should work just fine.