I am looking to get a hack n tap kit for my 242. I see that IRO has a kit and so does RE.

I see on the IRO site everything is 27 spline but if my rear diff (Chrysler 8.25) is a 29 spline, is that going to matter?

Also does that affect the use of an xj front drive shaft?

Jeep is a 2000 XJ with 4.0, AW4, NP242, Dana 30, and Chrysler 8.25

 

27 spline is for the count on the transfer case output shaft, not the axle shafts. so no it doesn't matter.

to run the front driveshaft, you need the IRO kit, the RE needs a custom driveshaft if I remember correctly. I looked into the same kit and when I have the money I'm going to go with the IRO one and a front driveshaft.

 

I used the IRO kit for a long time, was able to run a stock front XJ shaft on the rear with my 8.25 no problem