I want to put a 2001 Cherokee 2x4 4.0 engine and AW-4  automatic in my 1998 TJ with knocking 2.5 / AX-5. The 4.0 comes complete with wiring and the trany with linkage and shifter. The XJ was hit high on its side and is complete so i can use whatever i need.  What about using the 8.25 rear end or would the ratios be different. How do you find out the ratios. Would the 4 cyl. TJ ratios be lower than a 4.0?  

i know if you spin the tire with it jacked up one full turn of the tires and count how many times your driveshaft spins  then divide, that will give you a idea what gear ratio you have.
 i beleave in  the swap if you have access to all the stuff like the computer and ect.but then again im clueless and think anything can be done if you want it bad enough, look at my jeep for an example.
good luck