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Everything you ever wanted to know about the AW4

xeroOTG said:
I honestly do not remember. I pulled it off in my 93, which would be very similar. When I did it, I used a FSM. It was not hard, just fairly time consuming. The aw4 controller is fairly simple, it takes an input from the throttle position sensor, monitors the brake petal, transmission position sensor, and the output speed sensor (not the speedo drive). For the tps and the brake, it just sits in parallel to the other systems, so making it isolated should be fairly simple.

The tps adjusts the shift points and the brake petal is used to unlock the torque converter, so don't skip those inputs. Without them the TCU will function poorly.
Click to expand...


I've completely gutted the Comanche. I'm on another fourm Comanche club.com asking for nohow.. No one has any advise other than to sell my trans an t case an get the year correct set up... I'm not opposed too that option I just like the power comfort switch my aw4 has an its only got 30k miles put on by me so I know the trans an t case are sound... Any one have susjestions... How do I up load pics an keep this thread alive... Really dieing to get my jeep off camber again grrr. Selling my 10k snap on box for pennies can't get any calls on it at $3000 or calls on my sti swaped 61 Baja... Projects suck.. But my jeeps my life... Fkhhh the dash swap is a whole another story entire fire wall needs to be butchered out of the xj to make the swap clean.. An the aluminum steering column brace is going to need its mounting points wlded in... If anyone's see or heard it done xj to mj swap call me pm me helopp.... Thx....
 
This is off topic enough that I'd really like it if you guys could put it in another thread. It's kinda confusing this thread a bit.

Anyone have a pic of a stock 97 XJ TCU mounted in the stock location? I am looking for this because it is different from 96 down (different location) and 98 up (different TCU housing shape) and I'm not sure if something I want to mount near it is going to fit.
 
Milner said:
UPDATE:
I have not been able to work on it for a month or so. Finally got it back together today and it WORKS!!
So for anyone that comes looking, here is the summary. I used a 98 2wd aw4 with a 96 donor for a output shaft and output/adapter housing. After coming here I discovered that was a problem. I tried the 97 TCU with 96 sensor. it did NOT work for me. It has for others.
I found a 99 output housing, sensor, and tone ring. BUT discovered that the thickness of the tone rings are different and my 96 shaft did not have the proper snap ring grove for the 98+ tone ring. So, I used a piece of hydralic hose just under a 1/2 think to hold the tone ring on. It sandwiches between the tone ring and the input snot of the tcase. Since it is not submerged and not under and load, it should not cause a problem and will stop the ring from moving.
Hope this helps someone else.
Click to expand...

I had to do the same thing on mine (96 trans in a 99). I simply drilled and tapped the tone ring for a 1/8" straight plug (plus some loctite).

 
Quick question, Only thing different in 90.5-96 AW4's are the 23 spline output and 0.75:1 OD ratio right? So it could bolt up to a 87 XJ/MJ if the T-case is changed? Anything else that would need to be done to put a 90.5-96 AW4 in an 87?
 
Correct. You MIGHT have to change the throttle valve cable since it may have a different end at the throttle body (I forget, compare them) and you might have to splice a whopping 3 wires with butt splices, their color codes allegedly match and I'm pretty sure no splicing is required but can't remember 100%.

You can also just change the input gear in the tcase you have already as long as you use one from a 23 spline np231 made before 94.0 (they changed the helix gear cut halfway through 94) if you so desire. If you change the case out, use one from a 95 down or earlier if you intend to use a stock driveshaft and slip yoke since the rear output housing changed from 95 to 96; if you are installing an SYE at the same time this is moot because you will be throwing that stuff out and putting the SYE and a custom shaft in its place anyways.
 
Hi, I have done a swap and now my XJ is with an AW4. I am not using the TCU, I made a simple circuit with switches to change speeds. What I need to know is if I need install the Kick Down Cable to TPS or if I can leave it alone. Thanks!
 
33 pages, so much info. Great group of nice people.

96 XJ with 2WD, 4.0, AW4

Here is the problem: First and Second are fine, Third goes up to about 45mph
and then seems to be slipping. No overdrive. Tried to do the manual thing with
the TCU disconnected but same symptoms.

New solenoids and brake switch (nice to have backup lights again).

Is my AW4 borked and needs to be rebuilt or is there a chance it can be some
rather minor (lol) thing? NSS?

Trying to do as much of the work as I can, its cold and windy and I am 71 years old.
Any one in Southern New Mexico want to earn a few bucks?
 
Try cleaning the transmission position sensor. It is serviceable, and quite expensive, so don't just replace it.

Sorry, I don't have a link to a guide on cleaning it, but they are on here somewhere.
 
From the description so far I doubt it is the NSS unless the solenoid's power goes through the NSS switch, the NSS=Neutral Safety switch on the Jeeps? The NSS, which is called by other vehicles a range selector switch or transmission position sensor. There is a thread on here on how to pull and clean the NSS switch, but to my knowledge it does nothing in the manual selection, no power to the Transmission computer manual shift mode. That mode uses no power to the solenoids and uses the hydraulic pressure and actual shift position in the transmission to select the gears. In that mode you get first in 1, up to about 4500 rpm. You get third next (skips 2nd) in 3 (or D?) and then 4th in OD or D IIRC? Only way to get second is to down shift from 3 to 1 (or is labeled 1-2?) at about 35 mpg in third. In 1 (oe 1-2) it will down shift back to 1 hard at about 10 mph after slowing from 35 mph in 1-2. IIRC there is to TC lock up with the TCU computer unpowered. When it is electronically controlled it is hard to tell 3 rd gear shift from the TC lock up!!!

How old is the trans fluid? I think the 96 still uses Dex III (old stuff, not synthitic!!) only. And it has a life of only 25,000 miles. Have you tried multiple transfusions to flush out the old fluid? Try a 1/2 pint of Trans-X additive first, drive it about 5 miles and get it good and hot and run all the gears you can including reverse, then pull one of the Transmission lines at the radiator and run it in Neutral to pump the fluid nearly dry (about 1/2 gallon). Walmart has dirt cheap Dex III for about $13/gallon. Do that about 3 times before you give up to see if the problem goes away. More times than not it will solve the problem. Also have you dropped the bottom side pan and changed the filter yet? Ever changed the filter?
 
All the AW4s use mercon/dexron III. The reason I suggested it, is I had the exact same problem. My understanding is that OD selection is entirely based on the trans position switch and the torque converter lock up as well.

Also, it's free.
 
Ecomike and bigdaddyjlove, Thanks again for helping.

Trans fluid and filter changed less than 800 miles ago. Replaced the solenoids since
then so more new fluid. I will get some of that magic fluid and start doing drain and refills. My AW4 has a drain plug :shocked: can I use that instead of pulling a trans line?
Should I think about cleaning or replacing the filter in this process?

What about the two Valve Body Oil Tubes? Pull them and clean? (I got that idea
from looking at the AW4 manual)

Looking forward to tomorrow. Muchas gracias
 
The drain plug only empties about 2.5 quarts as I recall. I think using the radiator / Transmission line to drain it in Neutral gets more fluid out per draining, maybe 4 quarts, not 100% sure of that. No need to mess with the pan and filter at this time. The Trans-X uses solvents that dissolves sticky varnish from dead T-fluid and swells out o'rings and seals so they work again. The flush gets the dissolved gunk out. The Trans holders over 10 quarts as I recall, no way to drain it all once. Better to partially drain and refill and dissolve again.... than to try all at once.

Bigdaddy, he puled the power to the TCU which kills the NSS operation of the transmission and switches it to pure hydraulic mode. It disables the solenoids and then you shift from 1 to 3 to 4 using the floor shifter.
 
kastein said:
This is off topic enough that I'd really like it if you guys could put it in another thread. It's kinda confusing this thread a bit.

Anyone have a pic of a stock 97 XJ TCU mounted in the stock location? I am looking for this because it is different from 96 down (different location) and 98 up (different TCU housing shape) and I'm not sure if something I want to mount near it is going to fit.
Click to expand...

I wish I did. The only thing I can offer up is a drawing of the location and a pic of the '99 TCM. I can't even find an image of a '97 TCM

As you know the '97 TCM is sort of an odd duck - it's sort of between the '96 and the '98 (the change over year).

Anyway, hope these images help.

'97 - '01 location (FSM):

TCMLocation.jpg


My '99 TCM in place. The '98 (and I suspect the '97) have different mounting legs.

DSCF3024.jpg
 
Ecomike. Did four drains and refills with Trans-X.
1/2 are perfect. 3rd is perfect.
4 and OD still not working. 4 almost wants to but can't.

I have some other things to look at and a new NSS on the way.
If you have any new ideas I am ready to try anything, ANYTHING!

You have put me on the right track, just a little more.
 
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