Is one better than the other, about the same ? Also I have the Dana Rear in my 97 XJ, what would my front be? Or at least options it could be. I looked for a brand on it and found nothing...

 

It should be a dana 30, but could be high pinion or low pinion and there are different spline counts. What year/motor do you have? As far as the Tcase I dont know enough

 

Your 97 has a high pinion Dana 30 in the front, which is a good thing. The '96 to '99's are the best of the Dana 30's. They got bigger, stronger u-joints in '96. In '00, the front axle went to a low pinion design, which is is weaker and has less ground clearance.

I'm not sure about the 231 vs 231J transfer case. I was looking at buying a 2wd low conversion kit for my '97, but the one I was looking at said it was for 231J only. Anyone know for sure what was in the XJ's and what the difference is?

 

pretty sure all jeep np231's are np231j's, j standing for "jeep"

 

I just put one in my jeep yesterday, it says on the tag New Process 231 J.

 

a 231J the front driveshaft bolts in from behind the flange, a regular 231, as in one from a dodge, the front driveshaft bolts on from the front.
so a jeep front driveshaft with the double cardan joint is threaded, so the bolts go through the flange into the driveshaft, where as a dodge is the other way.

also, the shift lever is clocked differently.

 

Did your tag say a ratio? Mine was 272.