Transmission compatability quesion

[kyleag89]

I was wondering if a 94 aw4 trans will work in my 89 MJ? I found a aw4 trans with a np231 transfer case for $150.

[robfg67]

The good news:

The XJ Cherokee used the Aisin-Warner AW-4 4-speed automatic transmission with both the 2.5L I4 and 4.0L I6 from 1987 – 2001. This transmission will work in your MJ.

 

The bad news:

The '94 XJ used a HO (High Output) engine and will almost certainly have a 23 spline transfer case. Refer to this site:

http://www.lunghd.com/Tech_Articles/Tra ... roject.htm

 

Solution:

Pay $150 for this set-up, sell your 21 spline for $50 and buy a 23 spline.

[64 Cheyenne]

I think the OP is saying that he is getting the AW4 and 231 for $150. :thumbsup:

[Eagle]

The original post doesn't say what engine or tranny are in the '89. The '94 AW4 will work with an '89 4.0L, but it will require buying a new flex plate because the flex plate teeth are what trigger the CPS, and the Chrysler HO system is completely different and not compatible. Ditto if the engine in the '89 is a 2.5L, except that there you'll also need the appropriate bell housing and torque converter for the 4-cylinder engine.

[kastein]

Might be wrong, but I'm pretty sure he can use his old flexplate unless he's got a 2.5L - was not aware the AW4 came behind the 2.5L on that many years, I thought the ChryCo tranny was used for most of them.

 

You can use that trans and transfer case as a pair, as noted it'll be 23 spline.

 

You can use up to a 97 electrics-wise but aim for 95 and down since the slip yoke design is superior.

 

You may have to splice a connector onto the wiring harness for it, I am not sure if they used the same plug for the solenoid control harness on the RENIX and OBD-I AW-4s.

 

If you are converting from a manual to an automatic, as noted by Eagle you will need a year-appropriate flex plate since your rig is RENIX and will expect a RENIX flexplate. If you already have an automatic and are just replacing it, simply use your existing flexplate. If your torque converter is acting up, use the one from the donor vehicle, else, I would use whichever one has lower miles and/or better looking fluid in it.

[vhenem]

I just did a 91 AW4/242 Swap into my 2WD 88 MJ, I transferred my CPS into the tranny, kept my flexplate and it dropped in with no problems. With any luck the 94 will be the same and you should have no issues

[Eagle]

Might be wrong, but I'm pretty sure he can use his old flexplate unless he's got a 2.5L - was not aware the AW4 came behind the 2.5L on that many years, I thought the ChryCo tranny was used for most of them.

His post did not stipulate that the '89 has an automatic transmission.

 

Also, given the frequency of the flex plate cracking, I would not do a tranny swap without replacing the flex plate. I don't want to pull a tranny and transfer case that I just installed three months ago.

[kastein]

Might be wrong, but I'm pretty sure he can use his old flexplate unless he's got a 2.5L - was not aware the AW4 came behind the 2.5L on that many years, I thought the ChryCo tranny was used for most of them.

His post did not stipulate that the '89 has an automatic transmission.

 

Also, given the frequency of the flex plate cracking, I would not do a tranny swap without replacing the flex plate. I don't want to pull a tranny and transfer case that I just installed three months ago.

Good point there. Looking at RockAuto, they're only 50-60 dollars, not as bad as I was expecting.

[JeepcoMJ]

the torque converters between some years have different spacing on where they bolt to. you can redrill them on your flexplate to bolt it up, or use the original year torque converter ( never use a used torque converter with a trans it didn't come with)

[kyleag89]

Sorry for not clarifying.. I have a 89 MJ 4.0 4x4 auto with a AW-4 with the 21 spline count. I was just wondering if the 94 AW-4 with 23 count trans case will work with my set-up? I thought that it would be a direct swap but the TCU computer might be a problem?

[kyleag89]

Anyone have any input? I want to get my truck running again..

[Wildman]

The answer your looking for was posted above ^

 

Yes, the '94 AW4 will bolt up to your '89 Renix engine, but, you need to retain/replace the old flex plate with a new Renix flex plate, while you have things tore apart, because of the CPS.

 

You need to retain the transfer case with the '94 AW4 because of the 23 spline output shaft, your '89 231, 21 spline input transfer case will not work.

 

And Jeepco made the comment that the torque convert may or may not bolt up to the flex plate, and can be "made to fit"

 

Off the top of my head, the '89 TCU should be used, and I can't remember if the AW4 wire harness will just plug in or not :hmm: If it does not, there is a write up on splicing the wires to make it work.

 

And........$150 for the combo your getting is a good price :D

[kyleag89]

So it would be a safe to say that my 89 TCU will work with a 94 trans even if I have to cut and splice wires?

 

Also can I use my CPS with my flexplate in the 94 without any problems?

[Wildman]

I will say Yes on the TCU, I'm thinking a year or two ago, someone on here did swap in a HO AW4, and I think it was plug and play, but if you need to splice in some wires, we'll fine the topic.

 

NO, you can not use your Renix *87-90 CPS with a HO *90+ flex plate, or vice verse.

 

You need to have the Renix CPS and Renix flex plate installed for the ECU to get the correct readings. The same goes for the HO engines, you need the HO CPS and flex plate for the HO ECU to operate.

 

Your MJ is a '89, correct??? So you need the Renix CPS and Renix flex plate.

 

Eagle made a note that while you had everything pulled apart, it is a good time to replace the Renix flex plate with a new one, as they tend to brake in the center, and it would just be a good investment on your part for time and pulling the tranny again in a short time.

 

Maybe that's where your getting confused :dunno:

[kyleag89]

Thanks wildman.. I understand I meant to say I was going to use my 89 flexplate and cps with the 94 tranny.

[Wildman]

:thumbsup:

[kyleag89]

Trans is in!! The wires were plug and play... I was sooo shocked with my MJ today. I removed the exhaust from the header and the bolts came off like they were new. I have never in my life seen an exhaust come apart that easy.

[Wildman]

Glad to hear everything fell into place :clapping:

 

And that you didn't have any problems with the wire harness........I just couldn't remember if the wire were totally plug and play, which you prove were :D

 

Now.......what's this about the exhaust bolts coming off so easy :hmm:

 

That's one thing I've never seen :eek:

 

The only way I've ever been able to get the exhaust bolts off were by cutting or torching :fs1:

 

Maybe some day I'll find one that will un-bolt :roll:

[Pete M]

in my experience, exhaust manifold bolts either back out when they should stay put, or stay put when you want them out. :dunno:

[kastein]

Manifold bolts I've never had an issue with... ever. I've pulled (I think) 6 of em now and they've all come out fine :dunno:

 

Those blasted studs pressfit into the collector that hold the downpipe on though... :fs1: :headpop: :mad:

 

I generally get at them with a few extensions from below and round them off, dump a little rust, grease, and road grime in my face for good measure, then cut them and replace.

[kyleag89]

I really am still amazed myself that they came right off..

 

I have an issue though. My speedometer and odometer don't work.. What do I need to do?

[Wildman]

I really am still amazed myself that they came right off..

 

I have an issue though. My speedometer and odometer don't work.. What do I need to do?

 

 

 

That's one thing we forgot to tell you :doh:

 

Easy fix though :D

 

You need to swap out the quill from your '89 and install it into your "new" '94 transmission/transfer case.

 

'89 has a mechanical speed-o, and the '94 is a "electrical" speed-o.......I'm sure you seen the difference when you went to screw on the speed-o cable......didn't you??

 

The two quills just swap out, but take note where the one of the 3 "notches" are in relationship to the clamp, and install it the same way.

 

Here's Go-Jeep's write up on changing out the gears, but it will give you an idea what the quill should be set at. Just note that he's dealing with the electric quill.

 

http://gojeep.willyshotrod.com/HowtoSpeedoGears.htm

[kyleag89]

O man... I did put the 89 speedo gear into the 94 trans, BUT it fell out of the housing and I have no idea what position it was in.. Should I just play with it until it works?

[Wildman]

Well.....if you read up on Go-Jeeps article that I posted, it should tell you what position the quill sits in for your gears and what color speed-o gear you will need.......your axles should be 3.55, correct??? (4.0 / Auto)

[kyleag89]

Yep 3.55.. I have the right gear just not in the correct position. :hmm: I read another post I found that described it a little better for someone like me. :???: I will mess with it tomorrow after I address my 3 month old trans mount already making creaky noises!