some transmission and t-case questions

[ZJ_flexxxer]

ok i'm a little confused. i have an 87 comanche 2.5 with a 4 spd manual tranny.

 

what transmission do i have exactly? not sure if i have an ax-4 or t-4? and what transfer cases will bolt up to it if any?

 

i want to convert my 2wd to 4wd but i'm trying to figure out what t-cases will work and what won't. there are a few comanche's at my local junkyards but i don't wanna spend the time pulling a t-case plus spend the money on one and it not work.

[Geonovast]

You have an AX-4. 100% interchangeable with an AX-5. Same transmission, just the AX-4 doesn't have the internals for the 5th gear.

 

No transfercase will bolt up to your 2wd transmission. You need a 4wd trans. Probably easiest to snag a AX-4(5)/T-case combo from a 2.5 XJ/MJ/YJ.

[dasbulliwagen]

86 and 87 MJ's with the 4 cylinder, and manual trans came with the NP207 transfer case. I think they changed to the NP 231 after that, but I'm not 100 percent sure. If you swap in a 5 speed, your 5th gear won't be very usable, as 4 speed MJs usually had 3:55 gears, and 5 speed ones usually had 4:10 gears in the axles. This difference in axle gearing made the final drive speed between the two almost identical if you know what I mean. If you add a 5th gear to 3:55 axles the 2.5 likely won't have enough power to keep up. A swap to 4:10 axles at the same time would be ideal.

 

This is all assuming that any 4x4 trans you get will be 5 speed, as Ive never heard of one being 4 speed. I could be wrong. If they did, I'm sure the 4 speed version would be much harder to find anyways. Good luck.

[Geonovast]

I believe the first year for the 231 was 87.

 

Also, plenty of 4wd AX-4s out there.

[ZJ_flexxxer]

:fs1: ugh. i was hoping i could just bolt on a t-case and be done. i'm already swapping in a d44 with 3:73's and i thought now would be a nice time to throw in a t-case and drive shaft, then my old d30 from my zj when i do the axle swap on it. but looks like making the manche 4wd won't be as easy as i thought it would. :(

 

ok so this also leads me to a new question. will any ax-15 from an xj work in my comanche? i know where tons of ax-15's are

[Geonovast]

The AX-15 will only bolt to the 2.5 with a fairly rare early 90s Dakota bellhousing.

[mvusse]

I just found one of those fairly rare bellhousings in the Canton, OH Pull A Part, row 408. Don't know that I want to spend an entire day to pull the engine/transmission, and take them apart just for the bellhousing, though.

 

Also, even with 29" tires instead of the stock 27" ones my MJ has plenty of power to keep 70 or 75mph on level ground with 3.55 gears. And 24mpg at 75mph instead of the 19 I got with the AX4.