Trans , Xfer, etc
As long as you are staying with a manual, the 231s are all the same (at least in TJs). Same input spline count which is what matters. There MAY be some differences in the selector and the speedometer connectivity over the years, so you'll need to match this up when buying the SYE.
'97 TJ, 4.0, lots of good parts...
Sold and gone to Michigan
'06 LJ, 4.0, 42RLE, 241OR+2LO, HPD30, Rubi44, 4.88s
4.5" RE Superflex Short Arm, Bilstein 5100s, 9.5CTi, 35" MT/Rs... (phase 2)
Phase 3=Home-made 3-link front>>Phase 4=Trussed, RCVd, Rubi44 front>>Phase 5=ORIs (already purchased) and linked rear