i saw that teralow 4:1 low range kit for the np231 transfer case my question is whats the diffrence between the np231 that came in the jeeps and the 231 heavy duty that is in my truck just bigger chain or gears anyone know. also would a 241 fit a 1500 or are the output shafts diffrent

 

Check this out:

http://www.dodgeram.org/tech/specs/tranfer_case.htm

 

so basicly the chain is wider and the bearings are bigger no other real diffences so i could use that kit just would have to change the bearings?