My xj has the BA 10/5 in it currently. According to www.jeeptech.com
My question is: Is there a way to determine what output shaft I have with out pulling the T-case off. I have and extra AX-15 sitting at home and figure I might as well swap that in if My t-case will bolt up to it.The BA 10/5 is a light duty five speed transmission. It looks similar to the AX-15, but smaller and it is manufactured by Peugeot in France. The input shaft is 1 1/8" 10 spline and the output shaft can be 21 spline or 23 spline.
Also according to Jeep Tech again
How difficult would this be to do as well?If you own a 21 spline NP231 and you want to swap in a 23 spline transmission, you can either look for a cheap 23 spline NP231 at the junk yard or go to your local Jeep Parts Dealer and order up a new input shaft part #5300-6085. This is the part you need to convert your NP231 to 23 spline input
Paul