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AW4 PROBLEMS

XJROMEO

XJROMEO

NAXJA Forum User
Location
Gresham, Oregon
So on my way from browns camp and TSF I was coasting at 55 stepped on the gas to downshift and the transmission went straight to neutral and wouldn't go back into gear until I slowed down. So I went straight home and replaced the TPS. same thing. She won't shift into 3rd without placing it into 3rd manually or unless I get the rpms high enough then it will. Any other ideas what it could be???
 
I forget the what plug it is to test. I had a similar problem with an aw4. there is a "speed output sensor" on the top of the T-case. its a magnetic sensor that can be tested with a ohm meter.

here is the link to the thread I had going.

http://www.naxja.org/forum/showthread.php?t=1046951

Bronze.
 
lawsoncl said:
I would suspect the speed sensor is bad. That signal is on pin C3. For a 1990 it should have a 12-volt signal that gets grounded once per revolution by the sensor. The sensor itself is a magnetic switch that gets closed by a magnet on a rotor on the output shaft.

To test the tranny output speed sensor, use your meter to measure voltage between C3 and ground, with the TCU connected, ignition on, and engine not running. Chock the front wheels, jack up a rear tire, put the trans in neutral, xfer case in 2H. Now slowly spin the jacked up tire and you should see the voltage jumping between 12 (battery voltage) and near 0 (ground) volts once per driveshaft revolution.
Click to expand...
 
when was the last time you had the fluid pumped out of the converter and changed filter? id bet with those 35's you have pushed the fluid past its viscosity limitations. The AW4 is massively electronic. prepare yourself for a learning curve if fluid does not do the trick.

keep posting, ill help where I can.
Bronze.
 
That's what I was just thinking was draining the fluid out of the tranny and swapping the filter. But it's back to driving like it should it's weird how she's acting. I'll get to it in a couple days and let you know how it's going.
 
XJROMEO said:
That's what I was just thinking was draining the fluid out of the tranny and swapping the filter. But it's back to driving like it should it's weird how she's acting. I'll get to it in a couple days and let you know how it's going.
Click to expand...

So was it the speed output sensor?
 
Re: Re: AW4 PROBLEMS

Bronzewyrm said:
have you verified weather it is an electrical problem or mechanical?
Click to expand...

No sir. I jumped in her this morning to try and drive her to work sure thing she did the same get from first to second and not shift into 3rd unless I get the rpms up high. Now I did check the tranny fluid on the way home from TSF. However I didn't notice it was discolored. Nor did I smell how burnt the fluid was. The tranny fluid is most definitely burnt.
 
Bronzewyrm said:
have you verified weather it is an electrical problem or mechanical?
Click to expand...

XJROMEO said:
She won't shift into 3rd without placing it into 3rd manually...
Click to expand...
That leads me to believe it's electrical, right? ^

Here's a website I found with some good AW4 info.
http://mikestrawbridge.com/blog/2011/09/aw4-troubleshooting/

I haven't messed with the AW4 too much, so I can't offer too much advice. I'd maybe look into testing the solenoids. Seems like if only one gear is effected it could be a spotty solenoid crapping out.

Fluid change would be an easy fix, but I would think with bad fluid it would act up through all gears.
 
TORX said:
That leads me to believe it's electrical, right? ^

Here's a website I found with some good AW4 info.
http://mikestrawbridge.com/blog/2011/09/aw4-troubleshooting/

I haven't messed with the AW4 too much, so I can't offer too much advice. I'd maybe look into testing the solenoids. Seems like if only one gear is effected it could be a spotty solenoid crapping out.

Fluid change would be an easy fix, but I would think with bad fluid it would act up through all gears.
Click to expand...

I haven't refreshed myself on these in a year or so. BUT I have unfortunately tested and gone through just about everything in an AW4 system. I think you can unplug the TCU. it should be behind the dash on the passenger side. this should give you full manual control. in 1-2 you will have to rape the shit out of it to hit 2nd but all others should be manual select at this point. if you can get each gear one at a time. you have an electrical problem. Im With Torx, his thinking is legit. If you have already done a TPS, and replaced the output speed sensor. you should be down to a T.V. cable adjustment, testing each solenoid for problems, and finally a bad TCU.

if you can find somebody with the same year tcu as yours that is Known to work right you could swap them real fast to verify its condition. TV cable is easy to adjust. you would be then down to the shift solenoids.(I think one is bad in the pan) there are ways to test all this stuff you just got to do a little digging. its not a NEW to naxja problem im sure. I don't think it going to act up on you but check and make sure your reverse lights are coming on. if not, look to the NSS. The Tcu Is hooked into it.

this stuff may not make since in the beginning, but here in a couple days you will know the whole system. I got as far as tracing wires :rof: Don't be shy about posting up where your at with it. ill do my best to help you out.

Oh yeah, I have some spare solenoids here if you need. the JY wont let you jack them out of good tranys W/O buying the whole trans.

Bronze.
 
Re: Re: AW4 PROBLEMS

TORX said:
That leads me to believe it's electrical, right? ^

Here's a website I found with some good AW4 info.
http://mikestrawbridge.com/blog/2011/09/aw4-troubleshooting/

I haven't messed with the AW4 too much, so I can't offer too much advice. I'd maybe look into testing the solenoids. Seems like if only one gear is effected it could be a spotty solenoid crapping out.

Fluid change would be an easy fix, but I would think with bad fluid it would act up through all gears.
Click to expand...

That's a good read! I'm gonna do that TCU test tomorrow after I get off work and go from there! Thank yall for the help! I'm bound to figure this out haha on another note...

Once upon a time.... my transmission fluid was red.... The end....
a8u8u4y6.jpg
 
Alright!!!! So... I spent about an hour digging under my passenger side dash looking for the TCU. And about 5 secs looking under the driver side dash to find it there... So disconnected the TCU manually shifted from 1-2 good... shifted to 3 good.... shifted to D to get 4th gear..... Also good

So... that leads me to check solenoids next!
 
XJROMEO said:
Alright!!!! So... I spent about an hour digging under my passenger side dash looking for the TCU. And about 5 secs looking under the driver side dash to find it there... So disconnected the TCU manually shifted from 1-2 good... shifted to 3 good.... shifted to D to get 4th gear..... Also good

So... that leads me to check solenoids next!
Click to expand...

LOL glad you found it. Sounds like you have an electrical problem. Your almost there. Good to know the mechanics of the trans are good eh.

Bronze.
 
So another option and/or predicament. Yesterday after pulling the TCU harness and shifting through the gears and establishing it was an electrical problem. I plugged the box back in and the code the jeep threw was p1698. Now.... I looked up the code and I can't get the jeep outta 1st... even after I pull the TCU harness it's almost like it's in limp mode???
 
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