Everything you ever wanted to know about the AW4

[kastein]

1) yes, the OSS signal is completely different as well. This is covered by the first post, let me know if anything isn't clear.
2) should be the same, swap yours over. Dump some atf around where the tube goes into the other tube and spin it back and forth and it should get easier to remove. Replace the o-ring.
3) sadly, probably not, the yota trans will have a giubo joint or a metric ujoint and companion flange of some sort most likely while the jeep one uses a 1310 size ujoint. The yota may not have the same seal diameter or spline, either. And I believe your driveshaft length will be different 94 vs 96 jeep as well. Your slip yoke should work with the newer trans but the driveshaft length will almost certainly be several inches off.

I would have to check the parts catalog to be certain but I am pretty sure you would be far better off either getting the donor's driveshaft (assuming it has the same rear diff as yours) or getting the right year range transmission. 95 and down would be a good start but I am not 100% on that, I have never seen a 2wd auto XJ up here, only 2wd poverty spec manuals.

 

[Shadowdrop]

Thanks! I'm swapping my stroker engine and AW4 into a '74 International pick-up, so I've got quite a lot of adapting and swapping to do. On the other hand, I'm not limited by existing parts because I'm pretty much replacing everything!

 

[GODDESS]

i know this has been asked 1000x (i've read every thread on this already), but i just wanted to get expert opinions on an issue i've recently had with the AW4 on my '96 2WD XJ.
two months ago, i started up my Jeep and discovered that it was locked in 1st gear -- wouldn't even shift when i tried manually, except to R, N, and P. it turns out someone vandalised my car and cut through the wires on both O2 sensors and a sensor that goes into the side of the trans (TCU?). we spliced the wires back together and the Jeep ran fine...

until two weeks ago. i hit a bump on the offramp on the freeway and immediately my Jeep felt like it hesitated for half a second, then it locked itself in 4th gear (i was in 4th/OD when i hit the bump on the freeway). again, it was stuck in 4th, wouldn't even shift manually to 3/1-2. when i parked it and restarted it a few hours later, it was locked in 1st again.
after troubleshooting on forums, i removed the Auto Trans fuse and lo and behold, it shifts manually.

i work at a shop, but we don't do transmission work. we send trans work to another shop that immediately said "you need to replace your transmission!" when i took mine there... but i'm not convinced. without the fuse, my transmission shifts fine manually through 1-2, 3, and 4/D. there is no grinding or any weird noise, however it is leaking a very small amount but the head tech at my shop said that meant time to replace the filter/gasket.

i just had the TPS wiring harness replaced in July. haven't replaced either 02 sensors that had the wires cut and then spliced back together, but the engine runs fine, no rough idle, etc. no Check Engine Lights.

i just want to get a few other opinions before i make a decision. right now i'm thinking the culprit is whatever the sensor is that has wires going into the side of the trans that had the wires cut. i knew splicing them back together was a temporary fix, is it just time to replace it?

thanks & sorry for writing a novel!

 

[kastein]

You definitely need to recheck your splicing/repairs. I would put money on it being that.

Stuff to check:
OSS wiring - not having this will make the TCU think you are always stopped because it sees no pulses, so it will keep you in first until it sees something.
stuck in OD/4 is an interesting one. I suspect NSS wiring (passenger side of transmission, goes up along the dipstick) or solenoid wiring for that one. Solenoid wiring would mean it would shift manually still though.

Shadowdrop - ahhh yes, I forgot you were the guy with the international project. Good luck, sounds awesome! I believe the yoke off the rear output of an NP231 from the same year range (96-01 for this part) as the transmission donor would work just fine, but not 100% sure. You should be able to find someone to borrow/buy a stock rear driveshaft and/or slip yoke from on the SoCal chapter classifieds pretty easily to test out this theory since a lot of people do slip yoke eliminator kits on their 4x4 XJs. I am not sure if your 94 ZJ donor will have exactly the same color codes in the wiring harness, but it will probably be close. You can use http://bbbind.com/free_tsb.html (wiring diagram button) to look up full wiring diagrams for your donor harness, and I have a big notes file on what wires do what in a 1995 XJ harness I used as a donor to do an EFI 4.0 swap on a 1973 CJ5 last weekend. I can post a link to it if you would like. Guessing that around 90% of the critical signals should have the same color codes on a ZJ, the accessory and interior power stuff and the neutral safety switch signals are likely different however.

 

[Boss Cherokee]

I hate to bug you Kastein and I do not know if this has been asked without spending the whole weekend reading this entire thread!
My 99XJ 2wd 4.0 AW4 is whining. A brief history is that I changed all three internal solenoids 2-3 weeks ago because the TC would not lock up (code came up as T.C.) Everything went well except I put 3-4 qts DEX MERC III to fill it! I assumed that my 96 used it so would the 99! It started whining about 1-2 weeks after, slightly but now pretty noticeable. I went to get more fluid last friday because it was about a qt low and the auto clerk said it takes synthetic 4. It was a little low so I added about a quart of Syn 4. It whines pretty loud early morning when cold and shifts hard but is quiet as a kitten and shifts beautifully when it warms up! Did I ruin the trans with the DEX or should I just have the entire trans flushed with new Syn. 4 fluid???

 

[kastein]

Dex/Merc is the original factory spec fluid and the fluid that Toyota specs for their version, the A340. I believe it is also what Aisin specs for it.

ATF+4 (that's what you mean by the syn 4 fluid, right? If you meant Dex/Merc 4, you are fine) was specced by Chrysler after they stopped putting Dex/Merc in anything else and wanted to reduce the number of fluid types their dealers needed to stock. Whether it is better, worse, or the same for AW4s is a matter of intense religious debate and I refuse to get involved in that. :wierd: :spin1:

 

[lawsoncl]

GrimmJeeper did a thread on that at one point. As I recall the fittings are an M14 thread, unsure what pitch, and are O-ring sealed to the cast housing. Earls has adapters from them to a 37 degree AN flare, probably -6 or so.

Looking at http://www.naxja.org/forum/archive/index.php/t-1045807.html, I'm pretty sure that's correct. M14x1.5 o-ring thread to an AN-6 male.

Posting given Earls part number 9919DFHERL http://www.summitracing.com/parts/ear-9919dfherl I believe is the same as a Parker 6M14F8OMXS, which looks like this. http://www.mrostop.com/6m14f8omxs-parker-6-male-jic-by-m14-x-15-metric-o-ring-straight.html A hydraulic hose shop near you would probably have them on the shelf and even make you some nice hydraulic low pressure lines. Very little pressure on the lines, as they go to the cooler and then drain into the pan.
http://www.mrostop.com/6m14f8omxs-parker-6-male-jic-by-m14-x-15-metric-o-ring-straight.html

 

[Boss Cherokee]

Thanks and yes Syn 4 is abbreviated for ATF+4 (synthetic). I went ahead and had the trans flushed with ATF +4 and it seems to shift even better but I still have a little whine at start. I know they cannot get the torque coverer but I guess I'll try it again in 6 months if it's still together!

 

[GODDESS]

thanks very much for your help, kastein. :cheers:
a few more questions, just so i can be clear...

1) here's a photo of one of the wires that was vandalised. the electrical tape wrapped around the section we spliced them together is right next to some exposed wires behind the white clip, which from what i can guess is connected to the NSS on the other side of the trans, and one of the speed sensors? is that correct?
i have a 2wd '96 aw4, so no transfer case (i think).

2) Or should i troubleshoot the TPS and TCM first? also, where can i find a new TCM, or is that a junkyard part?

3) i've been driving it autostick for about a month now, but only two or three times a week, and only about 10 miles each way. am i taking a serious amount of milage off the life of the trans doing this? the fluid levels are fine, if not slightly brown-looking.

thanks again!!

 

[kastein]

TCM's a junkyard part... I suspect it's probably fine, they are fairly hard to kill.

The white clip is the wiring to your output speed sensor. You don't have an input speed sensor, since yours is a 96.

I am not overly familiar with 2wd models (aside from how to rip the 2wd transmission out and substitute a 4wd unit) but the NSS wiring normally stays entirely on the passenger side of the trans, goes up by the dipstick tube to the connectors to the passenger side of the valve cover right below the pinch weld in the firewall.

I really suspect your OSS wiring is at fault here, for at least 50% of the issues you have, possibly all of them if the wiring is picking up ignition noise sometimes and the TCU is seeing that as an extremely high output shaft speed signal and keeping you in the highest gear it has available as a result. So the vandalism of the harness right by that white connector is what I'd look at with the most care. If you can't find anything there that fixes it, then look at the NSS wiring on the other side.

 

[GODDESS]

kastein, you're a genius! :worship::worship:
i went out and unwrapped the electrical tape and found this:

this is my last post, i promise!! i'm sorry for temporarily hijacking this thread...

i stole someone else's image of their transmission from a previous page to help me visualize this better.

where the wires are cut (black wire marked in red circle on the 1st photo) is actually before the OSS connector (blue arrow points towards speed sensor), on a harness that pigtails up to the top of the transmission where i can't see (marked with a red arrow on the 1st photo, it has the large gray connector on the end at the bottom of the 2nd image), and down behind some kind of hose (throttle cable?) and into the lower side of the trans (marked in green on 1st image).
on the 2nd picture, there is a 3rd sensor right underneath the speed sensor that i don't have on my trans.

is this all one cable/harness?! what does that big gray clip connect to? i can't find the names of these parts anywhere, the closest thing was solenoid harness but google doesn't bring up much with even that.
i'd prefer to just get a whole new harness so that the splicing doesn't come apart again, but if my only option is to use the butt connector again then it's whatever.

thanks again!!

 

[1096xj]

Ok, I have gone through this entire thread and did not see (or maybe catch) an answer to my situation. I have tried the search as well. I have a 1990 Jeep Cherokee Limited with AW-4 and NP242 transfer case. The transmission seems to be shifting and operating fine in all forward gears. When I shift to reverse you can feel it go in like it should but on anything but level ground it will not go backwards. If I give it more throttle the engine just increases rpms with no reverse. Any ideas or help would be appreciated.

 

[klint96xj]

Ok, I'm attempting the 97 aw4 to 2000 swap. I didn't put the iss in cause I don't want to machine the case of the transmission. I exchanged the tcm and swapped in the 97 tcm to the 2000 xj. It is in and shifting but it is throwing the P0720 code which is the OSS. I know the OSS is different between years. Not sure what I should do at this point. Is getting the pcm and tcm reprogrammed an option? I took it to a mechanic and he said it seems like they are not communicating with eachother properly...

Would the 2000 OSS fix the issue? I know it's a different part though and won't just interchange without modifying the transmission case. I'm not a machinist and can't really do this...

Any advice? I just need it to stop throwing on the cel so I can pass emissions...

 

[kastein]

Check continuity on the two wires for the OSS all the way from the TCU connector to the OSS connector at the tail of the transmission. I'd almost put money on it not getting the OSS signal because of missing/swapped wires accidentally, post up how you spliced anything you needed to splice?

Also, did you use the 97 or 00 OSS? Assuming the 97, which is what you should have done.

 

[klint96xj]

I am using the 97 OSS because it is the only one that will fit where it goes.

As far as splicing goes, I used the 2000 aw4 harness, and any sensor that wouldn't interchange, I cut and spliced the wires to where the 2000 harness had new ends on it for the 97 transmission. I took time, and made sure the wires were right. They actually all where the same color and matched up, just had different ends. And obviously the 2000 harness had the plug for the iss which I just left alone.

 

[kastein]

Excellent. Sounds like you did it all right - do a continuity check on each pin for the OSS through to the TCU connector (my apologies, this is going to suck to do, sitting on your head under the dash... been there) and make sure the signal can get all the way through. It's either that or something else is keeping the TCU from seeing that signal.

Actually, I should verify the wiring, I haven't tried the 97 TCU in 98+ vehicle swap myself, just trusted someone else's experience in that it worked for them. Here goes:

97:
Schematic http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=9050
OSS is a 1ppr reed switch, ground referenced. Connects to pin 4 on the TCU, color code light green / white.

98-01:
Schematic http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=19756
OSS is a 4ppr variable reluctance sender, twisted pair signal to its own pair of pins on the TCU connector. Grounded through TCU pin 3, dark blue / black wire color code. Signal through pin 4 as before.

Since you used the 2000 harness, I suspect this is where the issue lies - you connected your OSS to the right two pins on it at the transmission end, but at the TCU end, that dark blue / black wire is floating around doing nothing, so your OSS isn't actually signaling the TCU. Try pulling it out of the connector (I wouldn't cut it just yet... that pin appears unused on a 97, but if you have to backtrack and put a 98+ TCU in it again, it's going to suck more if you cut the wire than if you just carefully pop the pin out of the connector housing) and grounding it at the TCU end, or simply splice a ground wire from the dark blue / black wire at the OSS under the jeep to a random ground to test the theory. If it works, you know what's up.

I'll clearly need to put some more thought into how to properly do the 97 TCU + transmission + OSS in 98+ XJ swap without hacking up any harnesses at some point. Guessing the person who reported that it worked (memasmuffin I think? I can't remember) either grounded the sensor in a different spot and forgot to mention it, or used a different method when splicing the harness that resulted in it grounding appropriately without more work, or swapped the 97 transmission harness or something.

 

[klint96xj]

Ok, thanks so much for the reply! I will try this when I get home today! That's a lot of brain racking! Lol

So just to make sure I got this right , the easiest way to test is probably grounding the dark blue/black wire on the transmission end and seeing if the thing works? Otherwise do it at the tcu.

Also, assuming that since the wire is going to pin 3 it won't matter if it is plugged in to the tcu or not since the 97 isn't using it. So it's basically all about grounding the sensor itself. Am I understanding that correctly?

Thanks again for the help? I really do appreciate it.

 

[klint96xj]

Well I found the wire you're talking about. How in the world do you safely remove it from the connector? Lol I unplugged it from the tcm and can't seem to get the wire to come loose. I know there has to be a clip holding it in to the plug, but it's so small that I canmt really tell... :/ lol

 

[klint96xj]

Ok, since I couldn't get the wire out of the plug. I plugged it back in and stock a metal wire into the pin #3 and grounded it to my drivers seat bracket just to test it. So far so good! I drove 7 miles and nothing has happened. Before this, t would immediately turn the cel on with a half mile of driving it. This is good news to me. Tomorrow when I get a chance, I will tie in to the transmission harness and ground it to the transmission itself so I don't actually have to mess with the harness under the dash.

 

[kastein]

Yup, you got it right. It shouldn't matter if you ground it without pulling the pin out of the TCU plug but I am reluctant to suggest this since I don't know if that pin is wired to something inside the TCU on a 97 for internal chrysler/aisin development work or something. Sounds like it worked, so as long as you ground that wire somehow you are good to go.