It might be better to just buy a used AX5. My AX5 was rebuilt about 6 years ago for about $400 (here in Mexico) and it is working well ( I only put about 1000 a year on the YJ, so even if the rebuild only lasts 20k or 30k miles, this is 20 to 30 years for me). However, I was able to buy a used AX5 from a TJ a few months ago for about $150. This is now my backup, ready to go in if and when needed. So buying good used AX5s seems like it could be a good low-cost alternative.