AW4 Swap parts
1) You need an AW4 - make sure you get an 87-95 anything newer than that gets a little more complex
2) You need to get a bellhousing from an 87-89 2.5L Cherokee with AW4, or you can get one from an isuzu amigo, trooper with the 3.?? v6
3) AW4's come in both 21 and 23 spline if you get a 91 -95 then you need a 23 spline transfercase
4) 2.5L AW4 torque convertor - they are a pain to find
5) flexplate from whatever year jeep you have - that will need to be redrilled for the AW4 torque convertor
6) TCU for 2.5L - these have different shift points than the 4.0L
7) Driveshafts will need to be modified - front one lengthened, back one shortened about 1.5"
Wiring harness for the AW4 - pull one from a cherokee that is the same year as your YJ
If you need more detail than that let me know