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Auto won't shift into OD

White Knuckle

NAXJA Forum User
Location
Tucson, AZ
1989 unLimited, 4.0l. The RPMS go up, but it stays in 4th. This has happened before when it got cold, but went away. I originally thought it was the Comfort/Power switch, but that doesn't change it. Maybe a vacuum leak, but everything looks okay. This happens after the engine warms up and it idles between 1K and 1500 in Drive.

New IAC, TPS, battery is only a couple of months old, all vacuum lines have been inspected and put in their proper place since my booster swap. Flux capacitor is in good shape too, but it takes a while to get to 88. :rof:
 
1989 unLimited, 4.0l. The RPMS go up, but it stays in 4th. This has happened before when it got cold, but went away. I originally thought it was the Comfort/Power switch, but that doesn't change it. Maybe a vacuum leak, but everything looks okay. This happens after the engine warms up and it idles between 1K and 1500 in Drive.

New IAC, TPS, battery is only a couple of months old, all vacuum lines have been inspected and put in their proper place since my booster swap. Flux capacitor is in good shape too, but it takes a while to get to 88. :rof:

Have you adjusted your throttle valve cable?
http://www.naxja.org/forum/showthread.php?t=1015963
 
Now why would you think it would be the TV cable? Please read again. It WON'T shift into OD.
Mine's an 88.
Odd as it may be, when I was sorting out my shifting problem (TPS wire was cut), that adjustment helped (after TPS problem was fixed and adjusted). Mine was going in and out of overdrive.
Did you adjust your TPS?
 
TPS is fine. TV cable is right where it needs to be. It is sometimes called a "kickdown cable," in the sense that it down-shifts. It idles high, so there has to be a vacuum leak somewhere, or maybe the MAP sensor is throwing it into closed loop...
 
No, it is NOT a kickdown cable, and those referring to it as such in the XJ/AW4 are wrong.

From the 90 FSM:

"The primary regulator valve modulates line pressure to the clutches and brakes (in the transmission, not at the wheels) according to engine load. The valve is actuated by throttle valve pressure. During high load operation , the valve increases line pressure to maintain positive clutch and brake engagement. At light load, the valve decreases line pressure just enough to maintain smooth engagement.

The throttle valve and downshift plug control throttle pressure to the primary regulator valve. The downshift plug and throttle valve are operated by the throttle valve cam and line pressure cable in response to the engine throttle position. Throttle valve pressure is also modulated by the cut-back valve in second, third, and fourth gear ranges.

The cut-back valve helps prevent excessive pump pressure buildup in second, third, and fourth gear. The valve is actuated by the throttle pressure and by line pressure from the second brake. The valve also helps regulate line pressure by controlling the amount of cut-back pressure to the throttle valve."

A "kick down cable" is just that--its sole function is to drop the transmission one gear under heavy engine load situations.
 
Thank you, Joe.

Next?

I'm going to go through it with a proverbial fine-tooth comb and come back with results. Gotta go through the other sites and see what I did last time this happened. It just went away before, buy why?
 
Bet its your transmission position sensor. The seletion for overdrive is electronic and if you get a bad switch, it won't shift into 4th.

there must be a dozen threads on this sensor. Search, and you can see how to clean it up instead of replace. They are pretty expensive.
 
Atlanta? Really? The home of those idiot housewives on TV? You must be mistaking TPS for NSS. NSS is bad, but that has nothing to do with OD. Do you own search and see if you get anything for "transmission position sensor" then get back to me. If anything, it would be a servo switch and I'd have bigger problems.

Next?

(I know what the problem is...any other brilliant guesses?)
 
Atlanta? Really? The home of those idiot housewives on TV? You must be mistaking TPS for NSS. NSS is bad, but that has nothing to do with OD. Do you own search and see if you get anything for "transmission position sensor" then get back to me. If anything, it would be a servo switch and I'd have bigger problems.

Next?

(I know what the problem is...any other brilliant guesses?)

Didn't you know? nobody is FROM Atlanta, so the insults don't really sting.

The NSS on an AW4 is more than just a neutral switch. It absolutley can keep it from shifting into OD. Had it happen on two separate cherokees.

If you know the problem, why are you asking for people to diagnose this thing from 1500 miles away?
 
No, it is NOT a kickdown cable, and those referring to it as such in the XJ/AW4 are wrong.

From the 90 FSM:

"The primary regulator valve modulates line pressure to the clutches and brakes (in the transmission, not at the wheels) according to engine load. The valve is actuated by throttle valve pressure. During high load operation , the valve increases line pressure to maintain positive clutch and brake engagement. At light load, the valve decreases line pressure just enough to maintain smooth engagement.

The throttle valve and downshift plug control throttle pressure to the primary regulator valve. The downshift plug and throttle valve are operated by the throttle valve cam and line pressure cable in response to the engine throttle position. Throttle valve pressure is also modulated by the cut-back valve in second, third, and fourth gear ranges.

The cut-back valve helps prevent excessive pump pressure buildup in second, third, and fourth gear. The valve is actuated by the throttle pressure and by line pressure from the second brake. The valve also helps regulate line pressure by controlling the amount of cut-back pressure to the throttle valve."

A "kick down cable" is just that--its sole function is to drop the transmission one gear under heavy engine load situations.
JP.....after saying that mouthful of words (nicely put I might add)....are you stating that it could possibly very well be the throttle valve cable adjustment then? And I did say possibly.............
I just know that it helped mine.
 
If you know the problem, why are you asking for people to diagnose this thing from 1500 miles away?
That's a good point there.:yelclap:
You must be mistaking TPS for NSS. NSS is bad, but that has nothing to do with OD. Do you own search and see if you get anything for "transmission position sensor" then get back to me. If anything, it would be a servo switch and I'd have bigger problems.

Next?

(I know what the problem is...any other brilliant guesses?)
You keep on on with the wise cracks towards those who are trying to help you and you might not get much help from anybody.
NEXT!!!
(I know what the problem is...)
Really now?
As for me .... your own your own then.
 
The suspense is killing me!!! White Knuckle, you have to tell us what was wrong with your tranny. I need to know if my guess to your particular problem is right or not.
 
The suspense is killing me!!! White Knuckle, you have to tell us what was wrong with your tranny. I need to know if my guess to your particular problem is right or not.


Nope. I wanna be just like the people who don't report back with the real solution, so that the people who actually use the search have to come back and start a new thread, then get yelled at by these whiney babies who "THINK" they have all the answers to search, further preventing progress.

I just happen to end up with the stumpers that nobody knows the answer to.
 
Nope. I wanna be just like the people who don't report back with the real solution, so that the people who actually use the search have to come back and start a new thread, then get yelled at by these whiney babies who "THINK" they have all the answers to search, further preventing progress.

I just happen to end up with the stumpers that nobody knows the answer to.

This coming from the guy who says it won't go into overdrive but then goes on to say that it stays in 4th. 4th is overdrive.

Fix your idle, it is way too high.

Now, if you are mistaking OD for TCC lockup, well then that is a totally different discussion. So Mr Brain, if you would be so good as to clear up your inaccuracies maybe all us whiney babies can come up with something.
 
Just to clarify:

I never said that I "knew" what your problem (the jeep one, not the other one) is. I tried to help be mentioning one thing that I knew could be the answer, because I have had it happen. I suggested a search because I am at work and don't have time to do a write up on how to diagnose and fix the issue. You responded with sarcasm, derision and arrogence.

There are members on this board with much more knowledge than I, so maybe they will want to help you. As for me, I am done with this thread.

Best of luck
 
Nope. I wanna be just like the people who don't report back with the real solution, so that the people who actually use the search have to come back and start a new thread, then get yelled at by these whiney babies who "THINK" they have all the answers to search, further preventing progress.
I just happen to end up with the stumpers that nobody knows the answer to.

Just because the solutions to our problem didn’t help you, didn’t mean what suggestions that were put up were wrong. They just didn’t work in your case.
And what’s with the attitude towards those that posted?
No one in this thread is whiney but you. :bawl:
This coming from the guy who says it won't go into overdrive but then goes on to say that it stays in 4th. 4th is overdrive.
Fix your idle, it is way too high.
Now, if you are mistaking OD for TCC lockup, well then that is a totally different discussion. So Mr Brain, if you would be so good as to clear up your inaccuracies maybe all us whiney babies can come up with something.
LOL:laugh:

I tried to help be mentioning one thing that I knew could be the answer, because I have had it happen. You responded with sarcasm, derision and arrogence.
Now I don't feel like The Lone Ranger.

So.... am I guessing that you just posted the thread to rant about your problems, so we would know what they are.... AND not to ask for help then?
 
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Stick to your guns White Knuckle. This place sucks and nobody ever wants to help anyone out. I, for one, can appreciate what you are doing. Thanks for making it easy. It's a tough love thing.
 
Now, now. What I am doing is not right. There needs to be changes, though. It seems like an endless cycle that dates almost all the way back when this site was a Vmag board. Geez, take a look at some other car forums if you think NAXJA is bad.

DieselSJ has come the closest with the lockup. The idle has still got me - has to do with it being cold and it must be that stinkin' temp sensor in the radiator; the engine warms up and the sensor in the head actuates the temp guage, but the rad sensor is still telling the computer it's cold.

Something so simple as CHECKING THE TRANSMISSION FLUID...

Still, that is no excuse, and I apologize for rippin' on you guys. It's really not my style. You gotta get a thicker skin - this is the internet. Jerks like me come through all the time - just leave them alone, stop coming back to the thread to make yourselves look just as foolish. Sure, come back to the playground, but move on to a better game.

The reason I signed up again (my old handle had been deleted) was to use the search. Boy, a lot of crap gets in the way!!!! I don't have time to fix JU...I think all hope is lost there.
 
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