stumper for you AW4 experts (yes I searched!)

[SLOPAR]

Hey all, newbie here, not to Jeeps just to XJs. I have searched your forum in great detail and performed all of the recomended things to correct my problem with no luck. So here it goes, my 1996 XJ will randomly not shift from first to second (about 50% of the time) unless you tach it up to about 4k. It also rarely shifts into O.D. (about 80% of the time), but then sometimes I get in it, start it up and it cyles right through the gears as if nothing at all is wrong! I have done the following: replaced the TPS with an Echlin, poured in Sea Foam, dropped the pan and changed the filter and fluid (followed by 50 miles, drain pan, add fluid 3X, fluid looks nice and red now), and replaced the TCU (no affect at all). I tried the "manual" test where you unplug the TCU and shift through the gears manualy and it sifts right through fine but still won't engage O.D. I'm at my wits end here with the fact it doesn't do it all the time. I don't have the money to put it in the shop right now so I am hoping you all might be able to let me know if I have overlooked anything. I really appreciate any advice given. Thanks!

[BrettM]

did you check the resistance across the solenoids?

[SLOPAR]

Not yet, I was a little afraid to try that. I don't want to risk damaging the plug trying to cram my volt meter down in there. If you think that is where I should be looking next let me know and I will give it a go. Also, I stumbled across a really good write-up on the process to do this with the specs. awhile back but I have not been able to find it since. If you know it please clue me in. Thanks a million!:worship:

[XJ4PLAY]

Just thinking out loud, or in type, but what about the Vehicle Speed Sensor (VSS)?
Would that have an effect?

[SLOPAR]

I'm not sure, anyone else think it's worth a look?

[xjtrailrider]

I had to replace both shift solonoids in my 96', but a different problem, it wouldn't shift back into first automaticaly, only manuely, no problems with OD. Turned out that the 1-2 shift solenoid just fried which according to my tranny shop, is a very rare occurance to the AW4(the SM had only seen one other in 16 years with the same problem) So I went ahead and replaced both solenoids...$900 parts and labor. The solenoids are $250 each.

Good luck!

[BrettM]

I had to replace both shift solonoids in my 96', but a different problem, it wouldn't shift back into first automaticaly, only manuely, no problems with OD. Turned out that the 1-2 shift solenoid just fried which according to my tranny shop, is a very rare occurance to the AW4(the SM had only seen one other in 16 years with the same problem) So I went ahead and replaced both solenoids...$900 parts and labor. The solenoids are $250 each.

Good luck!
You could probably find a low mileage AW4 for less than the $500 for 2 solenoids!

[lawsoncl]

I would start by checking the solenoids. Resistance as I recall is supposed to be around 11-16 ohms. Follow the cable from the drivers side of the pan up to the firewall. There is a connector there that you can break open and check resistance. Might be easier than fishing out the TCU again. YOu can find used ones on eBay, btw. I recently sold a set here for $20.

You say that the manual test, it stayed in 3rd? Or did you mean that the torque converter wasn't locking (some people mistakenly believe the tc lockup is the tranny shifting into OD).

[CrazyXJ]

I have the same problem sometime it shifts others it doesn't I've tried all the tech tips TPS, fluid, TCU neutral safety switch still not resolved trans has only 15,000 on it I wish I could figure it out also.

[lawsoncl]

I had to replace both shift solonoids in my 96', but a different problem, it wouldn't shift back into first automaticaly, only manuely, no problems with OD. Turned out that the 1-2 shift solenoid just fried which according to my tranny shop, is a very rare occurance to the AW4(the SM had only seen one other in 16 years with the same problem) So I went ahead and replaced both solenoids...$900 parts and labor. The solenoids are $250 each.

Good luck!

There are actually 3 solenoids. Two for the gear selection and one for t/c lockup. I think the $250 each is full dealer markup. I saw them somewhere for $135 recently, which is still a ripoff considering what they are. I can't believe they charged you $400 to swap two solenoids! It's a 1-hr job at most. Drain fluid, pull pan, one screw & connector on each solenoid, replace pan and refill. Really should take about 10 minutes more than doing a fluid and filter change.

[xjtrailrider]

Yep! I'm sure I got ripped I could feel it when I wrote the check! But I'm not a tranny guy so I just took thier word for it. Plus I use this Jeep for my landscape buisness and needed it back ASAP, time is money!

1-2 solenoid was fried. The other one and I'm not sure which, had really high resistance. I kept the old ones for a while and did a resistance check to confirm thier diagnosis.

30,000 miles since the repair and no problems, and I tow a 3200# bass boat on the weekends and a 2500# landscape trailer every weekday with it.
http://img485.imageshack.us/img485/360/jeepboatsideview2lr.jpg

[seymouj]

Not sure of any differences between your 96 and my 87 but I had the same symptoms and after swapping solenoids, tcu and tps with no change, I swapped the VSS and my problem was solved.
My FSM says it will not shift out of first if the VSS is not working (makes sense right because the computer doesn't think you are moving).
If I recall, it was a bit of a pain to get to because it was behind a bracket for the t-case linkage. I imagine it would be very easy on a 2wd and perhaps your 96 is different.
I had a parts jeep so I just swapped it but you can test it with an ohmmeter (analog is better). Just unplug the sensor and test between the 2 terminals while rotating the output shaft. It should behave like a switch opening and closing.

[SLOPAR]

You say that the manual test, it stayed in 3rd? Or did you mean that the torque converter wasn't locking (some people mistakenly believe the tc lockup is the tranny shifting into OD).
Now I'm not sure if the TC locked up or not, all I know is it shifted perfect but still no OD. Because it is shifting perfect in "manual" mode that has to mean it is an electrical problem right? I guess I need to bust out the volt meter and start doing some probing around. Thanks for the input fellas.

[BrettM]

It shouldn't be the VSS because he tried it with the TCU unplugged and it still didn't work right. When I swapped my AW4 in with just a manual controller (no TCU) I did nothing to hook the VSS up and everything shifts just fine.

[lawsoncl]

Not sure of any differences between your 96 and my 87 but I had the same symptoms and after swapping solenoids, tcu and tps with no change, I swapped the VSS and my problem was solved.
My FSM says it will not shift out of first if the VSS is not working (makes sense right because the computer doesn't think you are moving).
If I recall, it was a bit of a pain to get to because it was behind a bracket for the t-case linkage. I imagine it would be very easy on a 2wd and perhaps your 96 is different.
I had a parts jeep so I just swapped it but you can test it with an ohmmeter (analog is better). Just unplug the sensor and test between the 2 terminals while rotating the output shaft. It should behave like a switch opening and closing.

The output shaft speed sensor changed in 96/97 when they went to ODBII. The old sensor was a magnetic switch that made contact once per rev as the magnet on the rotor passed by. Like all mechanical things, it can wear out and stop working.

The ODBII sensor is a hall effect sensor like the CPS sensor so it's just a coil which shouldn't wear out. Instead of a contact closing, you get a voltage spike 4 times per revolution as the rotor went to 4 lobes. I found that out the hard way when I swapped a 99 tranny into my 89 using the 89 TCU - silly thing kept shifting at 1000 rpm. OBDII also added a front input speed sensor and will detect if the rear sensor is bad.

[badron]

Sir, get a manual transmission !!!!!!!!!!! My NV4500 has NEVER failed to go into overdrive.
Next week we are making our annual sacrifice to the Hurst God. We will be melting down over 2000 automatic transmission. To cast a 100 foot tall shifting tower. Witch will have a permanent home in our most holly of cities Muncie Indiana. Bring an offering to the smelting pot and receive a FREE "No thanks, I will shift for myself" bumper sticker.
There will be food and drink and drunken naked woman dancing about the open firer. So be there !!!!!!

[kennzz05]

my t/c wont lock either on my 98 if your t/c isnt locking you will notice the tach moving when you accelerate while at crusing speed when its locked the engine rpms only climb as the car speeds up (gentle acceleration)

[SLOPAR]

Well, I threw in the towel. I have an appointement at my local reputable transmission shop (my cousin owns it) next Wednesday. I will post up with what was wrong in case anyone is loosing sleep over the verdict.

[SLOPAR]

Well, it was a number two solenoid fault. I had them replace the soleniod, install an external trans. cooler and flush and fill. She is shifting like a champ now......only prob. is he told me straigh up they used ATF+4 not Dex. III! Am I cool or should I start the three quarts out three quarts in with Dex. III ASAP? Let me know fellas!

[BrettM]

go back to the shop and make them flush it. DexronIII/Mercon only.

[langer1]

Also 96 you should be able to have someone pull the transmission code for a starting point. A dirty Range selector (AKA NSS) could also be the cause.