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Can a bad NSS cause a shifting problem?

9

96 Cherokee

NAXJA Forum User
Location
Indiana
Just talked to a transmission shop about diagnosing my AW4 shifting problem and he said my bad NSS could be the cause. Searched some old threads and did not find anything relating the NSS to transmission problems.
 
Maybe, but doubtful. It would have to be claiming the shifter was in a different position. Usually the symptoms of a bad NSS are a refusal to start unless you wiggle the shifter or put it in neutral.

If you're shifting is messed up, more than likely it's the throttle position sensor (TPS) which is one of the primary sensors used to determine whento up or down shift.
 
What is your trans doing? Or not doing?
 
riverfever said:
What is your trans doing? Or not doing?
Click to expand...

Before it is warmed up in the morning, it requires high rpms to shift from 1st to 2nd gear. After it is warmed up, then it shifts fine the rest of the day. My Cherokee is used for rural mail delivery for about 5 and a half hours a day. From past experience, I do not believe it is the TPS.
 
OK...I also have a 96 and it was not downshifting for me the other day. As I was coming up a steep pass I had it on the floor and it stayed in 4th. An adjustment of the TV cable seems to have fixed it. Please let us know if it is indeed NSS. I didn't notice mine not shifting through the gears though.
 
This actually sounds like a TPS problem, other than the part where the problem fixes itself after warming up. It doesn't sound like NSS as it doesn't make any connections in Drive. Possibly a sticky #2 solenoid. I would check the tranny cable cable for proper adjustment as that's easy to do. Check the fluid level and make sure you used the proper fluid if it has been changed recently.
 
lawsoncl said:
This actually sounds like a TPS problem, other than the part where the problem fixes itself after warming up. It doesn't sound like NSS as it doesn't make any connections in Drive. Possibly a sticky #2 solenoid. I would check the tranny cable cable for proper adjustment as that's easy to do. Check the fluid level and make sure you used the proper fluid if it has been changed recently.
Click to expand...

I had this same problem with the OEM AW4 after it was rebuilt at a Chrylser dealership 4 years ago. I tried a new Mopar TPS right on the dealer's lot and it made no difference with that one. Now I am having the same symptons with this transmission. Last year, my TPS did go bad and caused severe transmission malfunction. A new TPS fixed it. This is way different. And I can think of no reason a TPS would be temp sensitive. Oh yea, with the other tranny they( the dealer tech) played with the kickdown cable several times. Never helped a bit. The solioids are something I know nothing about. If a solinoid malfunction can be temp sensitive, then maybe that is the problem. I would think the dealership would have checked that on the other tranny, but they never did find the problem. The other tranny fried at 15K miles after the rebuild and they were never able to get it to work, even after another rebuild and 3 new valve bodies.
 
AW4 woes

Since starting this thread I took my Jeep to a large transmission shop and let it cool down so they could drive it and see the symtons. The diagnostic tech plugged in a scanner and we drove it. I was wrong about it not wanting to shift into second. After a couple miles of starting out in 2nd or 3rd gear, it will then start out in 1st, but skips 2nd. It goes into 3rd once enough speed is gained in 1st gear. I believe he said the computer was telling it to shift into 2nd, but it refused. Anyway, they could not diagnose the problem and want me to bring it back and let them open it up and check into the valve body. The transmission has enough miles on it that I don't want to put a lot of money in it, and if they open it up, I can see that happening. So I drive it the way it is and continue to look for another AW4. I have searched old threads on this forum and the other Jeep forum and have not found anyone with the same symptoms. I am befuddled. And recently it developed a new sympton. Sometimes, when cold, it does not want to move in reverse. No problem backing out of my garage, but at the office I have started parking so I don't have to back up to pull into the loading spot. Once I get 3 or 4 miles into my mail route, the tranny is warmed up enough that it works fine the rest of the day.

PS. my mail carrier friend with a 98 Cherokee who paid the local Jeep dealer $3100 for a new tranny less than 2 years ago, just had to have it replaced again, with 42,000 miles on it. Local Jeep dealer has since went out of business so she took it to another Chrysler/Jeep dealer and they told her there were NO new AW4s available for right hand drives and they would install a reman for $3500 and ZERO warrany ! She went to a non-dealer repair shop and they installed a Jasper for much less than that with an 18 month warranty. As far as I know the AW4s are not RHD or LHD specific, they are the same. This makes the Chrysler/Jeep dealer look real bad in my book.
 
x2 What Lawsoncl said. NSS is out of the picture in Drive. Check the other items as he suggest.

Try moving the shifter into the 1-2 position and see if it's different. This forces the trany into only the selected gear(s). You could have a sticky solenoid.

You can find the AW4 service manual here if you want to read a bit about how it all works.

http://www.pirate4x4.com/tech/billavista/PDFs/index.html

Scroll down the Trasmissions section
 
Saudade said:
x2 What Lawsoncl said. NSS is out of the picture in Drive. Check the other items as he suggest.

Try moving the shifter into the 1-2 position and see if it's different. This forces the trany into only the selected gear(s). You could have a sticky solenoid.

You can find the AW4 service manual here if you want to read a bit about how it all works.

http://www.pirate4x4.com/tech/billavista/PDFs/index.html

Scroll down the Trasmissions section
Click to expand...

Although it has been a while back, I believe I did try the 1-2 and 3 postion on the shift lever and it made no differnce. Whatever the problem is, it's related to the temperature of the ATF. That's why I do not believe it's the TCU, TPS or tranny cable. Thanks for the link to the manual.

Edited to add: Looking at this manual reminds me of another symtom. When accelerating in first gear and it's skipping 2nd gear, (it won't shift from first to 3rd until about 25 mph), I notice there is no engine braking. If I back off the throttle before I get to 3 gear speed, it's just as if I am coasting in neutral. "No engine braking in the 1-2 position" is listed in the diagnostic portion. Another piece of the puzzle, but still unsolved.
 
Last edited:
Blaine B. said:
The Idle Air Controller is temperature sensitive if it is bad......but not the throttle position sensor.
Click to expand...

I admit I know nothing about an idle air controller, but I would think a big transmission shop would know to check that if it was a possible source of the problem. I am really stumped on this one. Is there any easy way for me to check the idle air controller?
 
I was just saying.......IAC doesn't have anything to do with the transmission.

To test the IAC you need a special device to see if the motor inside moves......but like I said its unrelated to your problem, I was just stating a fact :)
 
Blaine B. said:
I was just saying.......IAC doesn't have anything to do with the transmission.

To test the IAC you need a special device to see if the motor inside moves......but like I said its unrelated to your problem, I was just stating a fact :)
Click to expand...

OK, I misunderstood your post, but I see what you are saying now.

Thanks
 
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