You need a somewhat rare 2.5/AX-15 Dakota bellhousing, and also need some fancy shift linkage work, trans mount work, and different driveshafts.
After all that cost, you might as well have bought the rebuild kit for your AX-5 and kept things easier. The AX-5 is a good enough trans for a 2.5.
Most I would go for a decent one is 150, maybe a few bucks more if it comes with an external slave setup.