It doesn’t matter that the front of the transmission will bolt up, Jeep I6 to I6, the back will not. The 1973 CJ, assuming all is still stock, used the Dana 20 transfer case with what is referred to as a “Texas” bolt pattern as the pattern points resemble the state of Texas. The AX5 is set up for a round NP 231 which has a driver’s side front driveline drop; not compatible with a CJ front axle. You could use an adaptor, if one is made, to mate the AX5 to the Texas Dana 20 (passenger side front driveline drop) but the adaptor would be at least 4” long, maybe more and with the AX5 being 15-5/8” long the two pieces add up to around 20” in length. The longest transmission Jeep offered in your CJ was 11.9” (a T18 )making the AX15 & adaptor around 8” or so longer. With a T18 your jeep’s rear drive line is barely long enough without a lift and with a lift you are on the edge. I don’t see any way to make the AX5 work in a CJ5 as it is too long and we haven’t even started to talk about shaft lengths and spline counts.