'89 should have an AX-15 but you need a different trans for parts at the very least to convert it to 4x4. Easier to get a 4x4 AX-15 and tcase combo. (4 bolts hold the shifter on. BA 10/5 has only 3) External slave is better than the '89's integral one. If you stay 5 speed and plan on 33" tires, 3.73 or 4.10s are the way to go. I had a BA 10/5 and it ran great with 3.73 and 33/9.5/15s. With the auto it REALLY wants 4.10 and I'm looking for an 8.8 from an Explorer to put in. (It's up for sale at the moment for $3500 in Seattle)
"Usually found in a Jeep near Reiter, WA"
FOR SALE STUFF
'81 Eagle wagon with upgrades $2500
'87 Comanche shortbox 4.0/AW4/NP242 on 33" tires $3500