I'm new here, I have a AW4 problem...

Hi everyone, my name is Joe and I own a 94' Cherokee Sport with the HO 4.0L. I will try to keep this short and to the point I have searched throughout all of this forumn but can't really see a solution. AW4 probs seem tricky for some reason.
Ok, my Cherokee was a 2wd version. I bought a AW4 from Craig's list for $100 that was a 4wd version (1999). The transmission didn't work at all... no engagement whatsoever. I pulled it out and tore it down to remove the rear housing and shaft. I tore apart my perfectly good 2wd tranny and replaced the rear shaft w/housing. (bought a rebuild kit -gaskets and o-rings only) Put it all back together per the 1994 FSM. It worked 'ok' no slipping but would shift really late from 1st to 2nd.. and then after being warm.. would sometimes not go into OD or 1st. My solendoids checked out ok per the FSM. I manually tested them while they were in the tranny still in the truck... heard them click. (tested from the connector in the engine bay) I thought maybe the solenoids went bad for some reason..? maybe... changed them out with others that checked out ok with a test and VM readings... Same problem with the shifting. SOOOOO.... I said forget this rebuild stuff and the Phoenix 108' days working on this in the sun. I went to a junkyard and bought a tranny from a 2001 XJ. 20,000 miles on it and it came with the torque converter. $275. Warranted for 4 months. I put it in and did everything according to specs. The only thing I did was change the fluid and filter and transfered over my wiring to it so it would connect to my harnesses. I test drove it, it works flawlessly! BUT !!!!! BUT BUT BUT!!! once the temperture comes up to normal, circa 200-210, the transmission starts to shift later and later from 1st to 2nd and sometimes will not shift into first or OD. When at full 210', the transmission will not shift until about 4,500 rpm! I have also checked the power to the TCM, fuse and all. Everything good on voltage. I am assuming it is an electrical problem since it happens once the temps come up to normal operating levels. I am not a novice with electronics but can't seem to figure this out for the life of me !! I have replaced the TCU with another from a 94 XJ, no change. I have replaced the very rear speedometer sensor... no change. I have changed the TPS with a new one, no change. I have adjusted the throttle position cable, no change. The ONLY thing I have not changed is the ?TSS? a little blue sensor that is an inductor and senses the rotor inside the 4wd adapter housing. I HAVE tested that by pulling it and passing a magnet over it and it does show voltage occuring when i do this. (VM) Since this is also a 2001 tranny, it did have the 4 pole rotor within the 4wd adapter housing. I replaced that with the 2 ended metal one that looks like a bow-tie from the 4wd tranny I bought from Craig's list. (It was the same as the one in my 2wd tranny) I have checked all of the solenoids & their wiring. All good. I have rebuilt the NSS and the NSS works perfectly. Is it possible the my main computer ?ECM? could be faulty? Does the transmission solely work from its own TCM or in tandem with the main computer also??/ CAN ANYONE GIVE ME SOME INSIGHT ON TO WHY THIS TRANNY HAS PROBLEMS SHIFTING AFTER THE ENGINE COMES UP TO RUNNING TEMPS???? PLEASE ! THIS IS KILLING ME!! PLEASE PLEASE PLEASE !
Thank you for listening to my rant. I have turned my perfect running XJ into a basket case because of this transmission problem/swap.

Breaking things into paragraphs really helps.

Have you adjusted the Throttle Valve cable?

That's the output speed sensor... I'm not entirely clear on what you did. You need to use the sensor from a 97 or earlier as well as the rotor.

I'm not sure if that would make things behave that way though - try something for me... unplug the TCU from the wiring harness and try driving it for a while like that. You should get 1st gear with the selector in 1-2, 3rd with it in 3, and OD with it in D. It won't shift automatically but it will work "manually" and this will tell you if the hydraulic/mechanical portion of the transmission is OK or not. If it operates fine this way, you have some sort of a sensor/TCU/wiring/solenoid issue, if it doesn't, it's definitely a hydraulic/mechanical issue.

EDIT: Tom - yep, took me a while to find where he said it, but he did. That was the first thing I thought of too.

EDIT2: Yeah, this transmission runs off just the TCU. The ECU doesn't really have anything to do with it.

I'd try another TCU, since it handles all of the shifting commands. You could also wire up manual solenoid toggles and trace it out that way.

Good work with the rebuild and welcome to

Sorry about the runningonparagraph.
Yes, I have tried it without the TCU... shifts perfectly manually.
Yes, I have tried a different TCU from a 94', no change in shifting.
Yes, I have adjusted the Throttle Valve Cable, pulling it all the way back and then having someong press the gas pedal to the floor- making it ratchet into place.

Also, thank you for the quick replies!

Hmmm...
Sounds electrical to me! Fortunately that means it won't involve heavy lifting :roflmao: or more transmissions.

You already replaced the solenoids and verified them... same with the NSS and TPS. Did you check the solenoids after they start misbehaving though? Try driving it till it starts getting screwy, then disconnect that same connector and measure the resistance again. Each should be 11-15 ohms, if they are not, they are failing when hot and need to be replaced... again.

Also, can you clarify what you did with the output speed sensor? I need to know what year the following parts came from:
* rear housing (should be 97 or earlier)
* output speed sensor (should be 97 or earlier)
* output speed sensor rotor (bowtie, I think you are using this one, should be 97 or earlier)

I'm pretty sure from your explanation that you're using the bowtie rotor, but I'm not so sure on the rear housing and output speed sensor. The mounting location, at least on the '99 I pulled apart and started doing this swap on, was a different size from the '97 and earlier output speed sensor.

ok, I might have left out a couple of details so here they are:

Regarding the adapter housing and speed sensor:

I guess I am not using a pre 97 adapter housing, I am not using a pre 97 speed sensor but I am using a pre 97 bowtie rotor.

Wouldn't the wrong sensor/housing/rotor cause the shifting to NOT work entirely??? Why would this happen only when the engine is at operating temperture?

I am currently using a 2001 AW4 with the tail housing that it came with. It did have the 4 pole rotor in it (black) and the original 2 speed sensors. A sensor near the front of the transmission (near the bellhousing) and one on the rear (adapter housing): the sensors seem to look identical. (blue)
I removed the adapter housing and removed the 4 pole rotor. I then replaced the rotor with the aluminum (bowtie) 2 pole rotor. I installed the same adapter housing and speed sensor that I had just taken off to access the rotor. I do not have the front (bellhousing) sensor conneted to anything. (not needed for my year, 94')
Also, I do have another adapter housing that will fit the sensor that originally came off of my ORIGINAL transmission. This sensor is different than the one I currently have. It has a larger diameter and is longer. It will not fit into the current adapter housing I have on the transmission. (the current adapter housing hole for the sensor is too small in diameter)
I have attatched pics of my 1) current sensor I'm using & 2) what the original sensor looks like.


1) http://www.rockauto.com/catalog/moreinfo.php?pk=946127

2) http://www.rockauto.com/catalog/moreinfo.php?pk=933940

Hate to make you screw around with it, but you probably should use the adapter housing that fits the older style sensor along with the older style sensor. I have absolutely no idea why this would cause it to not work when hot, I'm kinda surprised it works cold!

My 96 fsm states (on page 21-171) that the OSS is a switch type, while my 98 fsm (page 74 of the aw-4 volume) states that the OSS is an inductance pickup that produces a voltage signal. So it's good solid info, I just can't explain why yours works at all using the 98/later OSS.

After reading the comments here, I DO BELIEVE that it IS the ouput speed sensor that may be causing the problem. Now knowing that the sensor is a switch (open or close) compared to the inductor style (varying voltage generated), more than likely this is for sure my problem. I did find a few articles on this site that explained the differences between the 98+ and the pre 98 tailshafts with sensor holes. I will have to pull the t-case and swap out the adapter housing with one i have from a pre 98 that uses the old style switch sensor. Wish me lucK !!
BTW... this site and most of its members is awesome !