Yes you have a 23 spline 231. If you have a good input shaft on your Tcase you can use virtually any 231 from a jeep. Even a YJ Case. All of the internals are the same minus the input shaft. That can easily be replaced in about an hour. YJ Cases use a vacuum module for the 4WD lights in the cab, but that can also be removed and replaced with the electrical connector on your TJ 231.