XJ Drive train compatibility

Sorry I'm a noob. I have a 1990 Jeep Cherokee Laredo 4.0L Automatic transmission 2wd.
I want to convert it to 4wd Automatic trans.
First I need to know what Parts I currently have and what parts I need to replace and what to replace it with.
For example will I have to replace my trans? If so which automatic trans are compatible with the 4.0L and will fit 4wd?
I just need as much info as possible on what configurations I can use and what vehicles I might get the parts from. If there is a resource on the web I can use to educate my self on the parts used in XJ drive trains, please post it.
I currently have the opportunity to buy a 1990 Cherokee 4wd with a 2.8L and Manual trans. for $400. However Im not sure if I can use any of the parts.

TIA

Anyone? Point me in the right direction

Alright man, here you go...

Transmission: Most just replace it, you theoretically can change the tail end of it over to the shorter version, but it's more trouble than it's worth, AW4's (the 4.0 liter's automatic transmission) are a dime a dozen.

Front Axle Try to find one that is not a vacuum disconnect model, in other words, if there's any hoses (aside from the differential vent tube) going to the transmission don't get it)
Front Driveshaft
Transfer Case
Transfer Case Linkage
Transfer Case Shifter & Bezel
Rear Driveshaft

It's not quite as bad as it sounds though, if you have an experianced person with XJ's with you I don't see a reason why it can't be done on one full day of wrenching. Just wonder though the bone yards looking for the stuff, I'd try to get as much of it off of the same vehicle as possible, just to keep from accidently getting wrong parts.

Sequoia

PS: We were all "noob's" once

That 2.8 might be a good donor for the axles and maybe a front driveshaft..... that's all I can think of right now (potentially you might get 4.11 axles out of it... but there is no way of knowing unless you run the vin or count the revolutions or teeth...)
In regards to conversion, in general your best bet is to find a donor vehicle and "rape" it for what you need:
1. tranny
2. tcase
3. front shaft
4. rear shaft
5. front axle
6. shifter assembly
7. center console
8. wiring to the 4x4 light

that's all I can think of the top of my head.... someone said at one point that you can get the tailcone output for hte tranny to make it mate to a tcase but... if you're going into that much effort... might as well get a tranny tcase from another rigt: maybe a newer model with a higher spline count??

Thanx for your replies. I guess what I need are the model numbers of the compatible parts or subtitutes. I have a Friend who is a mechanic and use of his Gararge, however I have to supply the parts.

For example:
what is the make model of the tranny?
Tcase?
Front shaft?
etc...?

Yes I know, I don't have a clue.

The only thing on the 2.8 that could be of use is....

the front axle. The front shaft will be shorter than yours by a couple of inches. And if you have a 8.25 the 4.10 or 3.73 gears are not going ot help you either. (Read regear you axle here.) Now if you have a D35 then you could swap both axles into your rig. Basically what Sequia and Remey have said with a slight bit of extra info. Of yea, check the front and make sure the joints do not look like this...... See the boot? Boot is BAD! U-joint is good.

Basically get a 4.0L AW-4, and 231 fromt the same donner if you can and both driveshafts.

talon39 said:

For example:
what is the make model of the tranny?
Tcase?
Front shaft?
etc...?

Yes I know, I don't have a clue.

Click to expand...

It's both not that simlpe nor it's that complicated... just go to a boneyard and pickup there at least the front and rear driveshafts, front axle (make sure the gear ratio is the same as you or you will have to regear), or use the axles from that other jeep... Primarily look underneath a 2wd and 4wd XJ and compare: see what's different, which big parts are on one and aren't on the other......

Thanks for your help. Unfortunately the bone-yard, is out of my price range. $1600 for the parts I need. However if I know what to ask for, I have other avenues to get the parts. I will try to get a good look at the 2.8L donor this weekend.

GSequoia said:

It's not quite as bad as it sounds though, if you have an experianced person with XJ's with you I don't see a reason why it can't be done on one full day of wrenching.

Click to expand...

I will tell you why you can't do it in one day or wrenching...... ou can't do it that way cause shit happens Come on... you should know that by now

talon39 said:

Thanks for your help. Unfortunately the bone-yard, is out of my price range. $1600 for the parts I need. However if I know what to ask for, I have other avenues to get the parts. I will try to get a good look at the 2.8L donor this weekend.

Click to expand...

Yikes.......! is that a yard that pulls out stuff for you or you pull yourself??? if the formaer., go to a latter one and ask at the cashiers window how much would they charge for transmissions, transfer cases and so on.... the $1600 really sounds like a bunch of bull

I will probably just buy the parts on ebay and from members here. I think I will save money that way. Unfortunately, I dont know what to ask for. Not even sure what the parts are that I have on my XJ right now. It would be great if I could find a compatible donor. Doesn't sound like the 2.8L donor will work.

That is actually about right.....

For the thieves around here. $700 for a tranny, $500 for a T/Case, and $400-$500 for a front axle! Find a U-pull it! also, check this site out.... http://car-part.com/

Hold it..watch out with the 2.8! I'm not sure about the front driveline or the transfer case on that, they changed.

What I would do.

AW4 Transmission (the only automatic that was mated to a 4.0 litre)
NP 231 Transfer Case (Identified by a tag in the back of it, and also by the fact it has 2WD - 4WD Part Time - N - 4WD Low, there is NOT a Full Time 4WD on this unit.
Dana 30 non-disco (as stated)

Preferably off one vehicle as I stated, the thing to be concerned about is the transfer case & transmission combo, I'm not sure if they changed the spline count on the transmissions output shaft / transfer case's input shaft, I think they did at some point...

Originally posted by Ghost
See the boot? Boot is BAD! U-joint is good

Click to expand...

Dude, I've never seen that...what's that from and what does it have under that boot?

So the 242 Tcase w/Full Time 4WD is not as desirable as the NP 231?

See why you should of come by my shop!

That is the orig. front axle on my 84 XJ! Its no longer under there. And under those boots are a CV ball joint??? I think that is what it is called.

Edit: The 242 just a little weaker but not by much.

I will post before and after pics when I get it done. I may take some pics of during as well

Are Commache Parts compatible?

Comanche parts are compatable except the rear driveshaft (it's longer in the MJ I believe).

Also, the NP231 vs. NP242 which is weaker argument is debatable, plenty of guys run 242's without trouble, so I'd say you'd be find with one strength-wise. But there are two reason that I suggest a 231

First, parts. There are more options with SYE's (which, if you end up lifting in the future will be something you may want) and with heavy duty tailshaft cones/wider chains.

Second, I just like to keep things as simple as I can.

Good to know Ghost-man..

There are two "basic" AW4's out there - the difference is not only the tailshaft housing, but the mainshaft is longer in the 2WD by a few inches. Everyone is correct that it is easier to replace it outright than to tear it down and rebuild it.

Find a donor (rollover vic?) and get the transmission/tcase/drivshafts/front axle all at once. Rear axles are the same, but get both driveshafts, since the tcase version is - naturally - shorter than the 2WD version. If you get the AW4 and tcase together, you are spared finding out which output you have on the AW4 (there are four versions of it, as I recall...)

You can use either the NP231 or NP242 - the NP231 will require a front disconnect axle while the NP242 will not (which simplifies vacuum wiring.) Getting the vacuum switches for the 4WD indicators is nice, but not strictly necessary.

Check your centre console and make sure you can pop out a blank panel and insert the tcase shift and bezel - get the donor console if you can't. The tcase shifter sits just to the left of the transmission shifter when installed, and I don't know what the 2WD centre console looks like.

Another possibility - one XJ is never enough. Look for another unit with 4WD, and buy it. The 2WD will make a nice parts-getter while you get what you need to "finish" the 4WD (D44's, lift kit, tyres/wheels, &c...)

Electronically, the 2WD and 4WD are otherwise the same (the control electronics for the transmission didn't change at all, and there is no electronic support for the tcase and front axle.) I don't know what changes were made to the front suspension to support the front axle, but it's a fairly safe bet someone else here has already done the conversion and may be able to help (or Eagle probably has a 2WD and a 4WD sitting SxS in his lot he can compare for you...)

5-90

I currently have the opportunity to buy a 1990 Cherokee 4wd with a 2.8L and Manual trans. for $400.

Click to expand...

I confused, did I miss something? What year is the prospective donner? I thought the 2.8 was only available in 84-86. If it is a 1990 it should have either the 2.4 - 4 cyl or the 4.0 - 6 cyl.

Chris