Hi, I'd like to convert my YJ to an automatic and I'm getting a whole wrecked 1990 cherokee, which is an Auto, for only $50. It seems the cherokee auto is better because of the 4 speed and overdrive. I've been told that it's longer than the tf999, which would cause problems with driveline length. Does anyone know how much longer it is? Could I make up for the added length with a SYE/CV shaft? Would it bolt up to my 4.0 even though the cherokee's 4.0 isn't a high output? Does it make sense trying to do the swap or will I just run into problems?

The parts will bolt up, but the Trans has a controller that talks to the ECU. You have to figure that out. Not sure of the details though.

Try a search ? Is the 90 the same as a 91 as to the eletronics? If so, try changing the whole harness out. I think the drivers are the same. (Drivers = running your gauges, ect. The pin outs might even be the same in the main connector.)

Do a search on the subject yet ????

:flipoff2:

Your wiring will be the same color code but the plugs will be differnt (gauges). As for hooking up the tranny putter im not positive how to do that. I have a aw-4 and 4L from a 92 XJ but i used the complete inside and out side wire harneses. It is longer but by how much i dont know right off the top of my head. I think the tf999 is 22.5" and the aw-4 is 25.5 ??

Yeah I did a search, and I found some useful info, but I didn't find anyone who has actually done the swap. Since I'm getting the whole truck, I'll have access to the harnesses. I don't think I could swap in the whole harness because the xj isn't the H.O. motor, is there any information on adapting just the tranny computer into my current harness?

Another option would be swapping the whole engine/tranny/transfer case from the XJ since it only has 90k miles. The non-H.O. motor only has like 14 less hp right? If I did this could I swap in the entire harness and computer to make it work? What t-case did the cherokees have?

look for a guy named beezil. he has the info you need. he posts here, but you can find him at naxja.org too.
as for 90-91, 91 was the first year for the HO motor, in 90 they were the non-HO, at least in XJ's.
Hunter

I did this swap. Email me or post your questions. I will do my best to answer all of them. Been driving my YJ with this conversion for about 4 months now...love it!

you should be able to graft the tranny putter on to you yj harness with no major problems. I will check my FSM and let you know what i figure out.

On 87-90 XJ's, the TCU is separate from the ECM and the two do not talk to one another. The TCU has it's own sensors to determine throttle position, etc. I agree, you should be able to graft it in without problems. I have the FSM for 89, and can photocopy/scan in anything you'd like. Let me know...if I can get PDF to work, I will add them to my website, which I am planning on updating the YJ project soon...

Sean, the HP differance is due to changes in the exhaust. I've just found a '96 4.0/AW4/231 to change out my 5spd. My understanding is that the AW4 OD is electronically controled - how did you manage this? Is there a way to lock-up the torque converter on command? Anyone have a schematic for this thing?
Thanks, mike

I read in JP magazine that AEV is putting the aw4 in to tj'sand they sell a kit to heop with the xj to tj auto swap

Originally posted by hybrid
Sean, the HP differance is due to changes in the exhaust. I've just found a '96 4.0/AW4/231 to change out my 5spd. My understanding is that the AW4 OD is electronically controled - how did you manage this? Is there a way to lock-up the torque converter on command? Anyone have a schematic for this thing?
Thanks, mike

Yes it is electronically controlled. Older systems (Renix) have a separate TCU that controls the AW4. This span was from 87 to 90. 91+ systems have the TCU controls built into the ECM. As long as you convert the whole shabang, 4.0/aw4, you'll be coolio. I put the older Renix system in my YJ, along with the AW4, all from an 87. I love it. I can power brake my YJ w/ 31's now.....hehehe.......or pull a posi hole-shot for about 10-15 ft.

Btw, to answer your second question, yes you can control the lockup feature manually if you prefer. check out www.naxja.org, those guys have priceless info on the XJ's and AW4's. Get a schematic from someone there and they'll help you out.

Chris

tys, could you go into more detail on how you did the swap? How did you hook up the TCU? Did you rewire the entire jeep or did you just splice?

I have heard that the aw4 does not allow you to select 1st or 2nd, as there is only one detent. How did you overcome this (if you did)? What did you use for a shifter?

Any other modifications and/or sensors needed to make the tranny work properly?

Thanks, Joe

July issue of JP magazine has soem info on this (and other) swaps. Might want to take a look at it, if you need any more info.

I replaced my 94' YJs 2.5L/TF904 with a 95' XJ 4.0L/AW4. I used the YJ harness for a starting point and merged it with the XJ harness (real fun?!?!). The XJ bulkhead is completely different from the YJ and the 2.5L did not have everything for the 4.0L like the 2 extra injectors.

There are still a couple of small issues to finish like a floor shifter to replace the column shift because the column shifter from the tf904 only has p/r/n/d/2/1 and you will need p/r/n/d/3/2/1. The tf999 is the same configuration as the 904. The computer will need to be linked into the ECM to get the engine RPMs. The overall length difference is about 4" if I remember right.

The transmission can be shifted into 1/2/3/4 even without the computer so don't worry about that. The computer will handle shifting from 1-4 in D and you can do it manually if need be.

The transfer case plate will need to be modified to accept the different transmission mount (just need to drill 4 new holes). I have a SYE which helped, but unless you have a SOA you are going to have a short shaft of about 15" of less. I ended up doing a SOA during this conversion to get the extra length I needed.

If you need any information you can find books on Chrysler repair manuals that will give you all the wiring diagrams for both the YJ and XJ Chrysler Manuals (http://www.techauthority.daimlerchrysler.com/) . The one I bought was $59 and covered the 94 & 95 YJ/XJ. These are the books the dealer service centers use. It is about 3" thick and covers EVERYTHING from bumper-to-bumper including diagnostics (manual/electronic), how to tell if something is working correctly and how to fix it.

If you have any questions you can email me and I will be more than happy to help.

Animal... Cheers :beer:

Originally posted by tys


91+ systems have the TCU controls built into the ECM. Chris Hummmm, my 91 has the TCU under the passinger side dash :rolleyes:

The 95 XJ AW4 I have has a seperate TCU that WAS under the passanger side dash. These are seperate units that can be unplugged and replaced. The transmission can be operated semi-manual with the shifter if the TCU fails.

Originally posted by Animal
[B] There are still a couple of small issues to finish like a floor shifter to replace the column shift because the column shifter from the tf904 only has p/r/n/d/2/1 and you will need p/r/n/d/3/2/1.


Wrong! At least on my AW4, which came from an 87. It has P/R/N/OD/D/1-2, so only 3 forward positions, not 4. Your column shifter would work with mine just fine.

The overall length difference is about 4" if I remember right.

I swapped out an AX5/NP231 from an 89, swapped in an 87 AW4/NP231 and the difference was only 2.5"

The transmission can be shifted into 1/2/3/4 even without the computer so don't worry about that. The computer will handle shifting from 1-4 in D and you can do it manually if need be.

Wrong again, well almost. True, the TCU will control 1-4 shifting while in OD, but it will also control 1-3 shifting while in D and also control 1-2 shifting while in the 1-2 position. The only way to get 1st and to keep the TCU from shifting into 2nd is the put your own solenoid control switches in your dash. Easy mod. Lots of XJ owners on NAXJA.ORG have this mod. I have the service manuals and schematics to prove this on my PC system at work. Tell me where you want them and I'll gladly send a copy.

Originally posted by harsanyj
tys, could you go into more detail on how you did the swap? How did you hook up the TCU? Did you rewire the entire jeep or did you just splice?

I have heard that the aw4 does not allow you to select 1st or 2nd, as there is only one detent. How did you overcome this (if you did)? What did you use for a shifter?

Any other modifications and/or sensors needed to make the tranny work properly?

Thanks, Joe

Sure Joe...I grafted the XJ Engine harness to my YJ's first, at the firewall. It was the hardest job. I matched up signal names from the XJ to signal names on the YJ harness, and soldered all connections (wrapped in heatshrink). I then moved to the TCU. Mounted it first, then ran the wires. I think there were only 5 or 6 wires that I needed to connect. A ground, a power, the Power/Comfort switch (you don't NEED to put this in, but I did in case I decided to tow with my rig, it shifts the trans at a higher RPM when in Power mode. The newer 91+ ones do not have this feature). Also the brake switch, which is to unlock the torque convertor when brakes are applied. The TCU also needs a TPS signal input, but the 87-90 versions have a separate TPS mounted on the t-body, so it was only a matter of plugging the connector back in.

To overcome the AW4 shifting into second while the shifter is in the 1-2 position, you can put in your own electrical switches to control the solenoids internal to the aw4. Some guys have done it on the NAXJA.ORG board. Mine actually doesn't shift into second when in that position, because something is wrong. I haven't bothered fixing it cause I don't want it to shift while in that position. All other shifter positions work as intended.

I used the XJ shifter and cable. The cable rubber grommet fit perfectly into the old clutch master cylinder hole. I made a custom console and mounted the shifter to it. Works great. Also had to build a different t-case bracket, no biggie.

Other mods I had to make where trans mount, d-shaft shortened (rear only, front was ok), breather tube for trans (already had one for the t-case), and cut a hole in the firewall for the tcu harness.

The XJ harness is HUGE. Don't be afraid. Get the schematics and follow them through for both vehicles. I found 2 mistakes in my 89 service manual (which covered both YJ and XJ models for me, so I only had to buy 1 book). Easily overcome because they were missing power wires!

One more tip, while the AW4 is out, drain the fluid, open it up and change the filter, test the solenoid (again easy to figure out with the schematic), also rebuild the NSS. The dealer will sell you a new one if you prefer, but they cost $325. Open it up, clean the contacts (watch for the small springs), apply ample amounts of dielectric grease, and slap it back together. Test continuity with a DMM, again, based on the schematics. Its just a switch that tells the TCU/ECM what position the shifter is in. Needed for operation and start. It also turns your backup lights on when in reverse.

Lemme know what else I can help with. I love this swap!!

Chris

tys & animal, thanks for the responses!

I've got a 95 YJ 4.0 AX15. I am going to keep the same engine. Can I just bolt in the tranny and hook up the TCU wiring? Or, do I have to get the whole XJ engine harness/ ECU? Do you know of any aftermarket floor shifters that would work (since I don't have a column shift)? It sounds like a pretty straight forward swap, but not many people seem to have done it.

Originally posted by tys

A ground, a power, the Power/Comfort switch (you don't NEED to put this in, but I did in case I decided to tow with my rig, it shifts the trans at a higher RPM when in Power mode.


Thanx I was wondering what that was for. That's the one thing my manual didn't show anything about.

Originally posted by tys

I swapped out an AX5/NP231 from an 89, swapped in an 87 AW4/NP231 and the difference was only 2.5"


The TF999 overall case length is 16" and the AX5 overall case length is 22.5". We're talking about the difference between a TF999 and an AW4 . Let me se, you said that the AW4 was 2.5" longer than your AX5. If you take the AX5 at 22.5" and add the 2.5" thats 25". Isn't that 9" longer than the 16" TF999? That's not right either. If I remember the measurement I took when I first compared the transmission it was either 4 or 6" longer than the TF904. The TF904 is the same length as the TF999.


Originally posted by tys

Wrong again, well almost. True, the TCU will control 1-4 shifting while in OD, but it will also control 1-3 shifting while in D and also control 1-2 shifting while in the 1-2 position.

Really.. So tell me why the XJ console shifter has 1/2/3/d? Seems pointless to put a 1 on there when according to you it really means 1-2.

The information about the transmission shifting I was giving was from the Chrysler service manual. The removal and testing of the AW4 TCU involves manually shifting the transmission from 1st thru D to test the solenoids and the TCU functionality.



:flipoff2:

Originally posted by harsanyj
tys & animal, thanks for the responses!

I've got a 95 YJ 4.0 AX15. I am going to keep the same engine. Can I just bolt in the tranny and hook up the TCU wiring? Or, do I have to get the whole XJ engine harness/ ECU? Do you know of any aftermarket floor shifters that would work (since I don't have a column shift)? It sounds like a pretty straight forward swap, but not many people seem to have done it.

I purchased 2 B&M shifters to replace the column shift and stock tcase shifter on the floor. The new tcase shifter was a generic automatic tranny rod type shifter that I modified by using the original shifter rods from the column shifter. The other shifter is a 4-speed automatic tranny cable type shifter to replace the column shifter. Now I have 2 new shifters on the floor and they work great.

When you install the AW4 the transfer case sits back far enough to make it a real pain to use the stock tcase shifter. You will want to look into getting some sore of replacement. The option I used is not for everyone, but I love it. I never liked the stock tcase shifter anyways..

Originally posted by Animal

We're talking about the difference between a TF999 and an AW4.


Talk about whatever you like....I just referenced the difference between my 89 YJ parts and the 87 XJ parts I swapped in.


Really.. So tell me why the XJ console shifter has 1/2/3/d? Seems pointless to put a 1 on there when according to you it really meanS 1-2.

Oh...my bad. Maybe they changed in the later years...Mine came from an 87 XJ limited and only had 3 positions. I know this is the same for years 87-89, as I have the FSM that shows it. I assumed it was the same for all other years the AW4 was offered, based on reports I read from NAXJA about them being identical for all years.?.?


The information about the transmission shifting I was giving was from the Chrysler service manual. The removal and testing of the AW4 TCU involves manually shifting the transmission from 1st thru D to test the solenoids and the TCU functionality.


You don't need the TCU to test the solenoids, which makes it nice for benchtop debug. Hell, even if it's in the vehicle, testing the solenoids can be done with the TCU disconnected, some jumper wire and a 12v DC source. You only need a DMM to test the NSS which in most cases causes your trans to not function properly or even your vehicle to not start at all.

So... :flipoff2: yourself pal!! :D:D

Originally posted by harsanyj
Can I just bolt in the tranny and hook up the TCU wiring? Or, do I have to get the whole XJ engine harness/ ECU?

If you get the older version, is 87-89, yes, but you'll need to fabricate a second TPS switch onto your throttle body. It's an easy mod that is documented online. I have a link to it at home if you need it. If you go with a later model (90+), you will need the harness as the TCU signals are integrated into the ECM wiring/sensors.

Do you know of any aftermarket floor shifters that would work (since I don't have a column shift)? It sounds like a pretty straight forward swap, but not many people seem to have done it.

Nope, like I said before, I used the XJ shifter/cable setup. Nothing wrong with it and its a very solid shifting unit. If you are careful with the removal, you can save the top plate with shift indicators and the light and integrate that unit into a custom console. I liked the factory YJ t-case shifter, unlike animal, so decided to build brackets to make it work rather than buy a new one. To each his own...

Let us know what you decide to do, how you did it and what you think. You are right, not many have made the conversion, but MANY are talking about it. It seems to be the latest rave....

Originally posted by tys


You don't need the TCU to test the solenoids, which makes it nice for benchtop debug. Hell, even if it's in the vehicle, testing the solenoids can be done with the TCU disconnected, some jumper wire and a 12v DC source. You only need a DMM to test the NSS which in most cases causes your trans to not function properly or even your vehicle to not start at all.


I now that, but a quick way of testing to see if a transmission problem is with the TCU or the solenoids involves testing the tranny by removing the TCU and manually shifting the transmission. Just a quick method of testing, but I appreciate what you are saying.. really..

Now are we done hurling testosterone at each other? :D

Originally posted by Animal


... a quick way of testing to see if a transmission problem is with the TCU or the solenoids involves testing the tranny by removing the TCU and manually shifting the transmission. Just a quick method of testing, but I appreciate what you are saying.. really..

Now are we done hurling testosterone at each other? :D

Ok now I follow you. Yea, you are right about that.

10-4 on the Testosterone mang...

:beer: :beer:

Can I leave my factory computor alone (92YJ 5spd) and just add the Cherokee computor (96 AW4) ? I was thinking about just tapping into the needed sensors just to drive the second computor for the AW4. Will this work?
I have the AW4 allready, no harness or 2nd computor yet so I'm not sure how easy (or foolish) this project may be.

Originally posted by hybrid
Can I leave my factory computor alone (92YJ 5spd) and just add the Cherokee computor (96 AW4) ? I was thinking about just tapping into the needed sensors just to drive the second computor for the AW4. Will this work?
I have the AW4 allready, no harness or 2nd computor yet so I'm not sure how easy (or foolish) this project may be.

Probably not. Check with the gang over at NAXJA.org. They maybe able to help. In your case, I'd get the schematics for both years/models and compare them. You may get lucky and be able to remove your YJ ECM and replace it with the XJ ECM, adding the AW4 harness as well.

Chris

TYS I would like to know more about the modification that keeps the AW4 from auto-shifting into 2nd gear. 'cuse me while I remove my foot from my mouth'. I use 1st for a steep downhill control and do not like the idea that the tranny has a mind of it's own in that respect. I checked out naxja,org, but they are having technical problems with their forums right now. Can you tell me more about the mod and how I can do it. Can I just cut the speed sensor to the tranny and have this work?

Originally posted by Animal
TYS I would like to know more about the modification that keeps the AW4 from auto-shifting into 2nd gear. 'cuse me while I remove my foot from my mouth'. I use 1st for a steep downhill control and do not like the idea that the tranny has a mind of it's own in that respect. I checked out naxja,org, but they are having technical problems with their forums right now. Can you tell me more about the mod and how I can do it. Can I just cut the speed sensor to the tranny and have this work?

This pic should help you understand how the solenoids operate. You could put the shifter into the 1-2 slot, then use a rocker switch to open the wire that feeds the valve body solenoid #2, so that it never gets power to engage, putting it into 2nd gear. Let me know if you need more explanation. Also, PM me your email and I will send you the manual I pulled this pic from. It is the offical ASTG Manual for the AW4. Very good to have on hand!!! It's 4mb though.

Chris

http://home.stny.rr.com/ctatar/images/AW4_Solenoids.jpg