Please help me - AW4 Transmission Issue

[adiga101]

hi all i have jeep xj limited 1990 automatic
i have a problem in transmission i think when i go to highway the 3 & 4 gear it keep moving from 3 to 4 also from 4 to 3 if its on 4 & i push the gas its die i change the tps & still happen i disconnect the throttle cable also still the same
i have a power bottom when i push it & go to highway there is no problem if i return it to normal the problem back please help me
i think its a electrical problem ???? please help

[Mudderoy]

hi all i have jeep xj limited 1990 automatic
i have a problem in transmission i think when i go to highway the 3 & 4 gear it keep moving from 3 to 4 also from 4 to 3 if its on 4 & i push the gas its die i change the tps & still happen i disconnect the throttle cable also still the same
i have a power bottom when i push it & go to highway there is no problem if i return it to normal the problem back please help me
i think its a electrical problem ???? please help

This sounds a lot like the problem I had when I put 32" tires on my lifted Jeep. When going down the highway at 65 or 70 mph as soon as I hit a mild overpass I'd start slowing down. If I was in cruise control it would kick down to 3rd. That's the only time this happened to me. I went about 6 months until I replaced the 3.55 gears with 4.56. It stopped doing that as soon as I changed the gears.

This is probably not your issue since you'd know if you were having to press the petal before it waffled between the two gears, but it sounded really similar to what I experienced.

[4.3LXJ]

Sounds like the typical hunting of gears at highway speed. How far is your throttle depressed when this happens?

[89Laredo]

The power/comfort button is useless. Keep it in power.
92+ are wired in power
.
Sent from my Milestone X using Tapatalk 2

[Superkirby]

My 93 does the same thing. I just assumed it was the way it's supposed to work? For the most part, the roads I drive on regularly I can run about 65, maybe 70 tops. At 70 it will be fine unless I really step on it. Drop down to 65-68 and it will stay in 4th as long as I'm on a level surface and don't ask anything extra at all. At 65 if I go up even a small hill or hit the gas much at all it drops back to third.
Sadly, I find myself turning into the guy that won't go over 60 to try to save gas. I used to hate that guy. Now I'm him.

[Mountain Goat]

Sounds like time to re-gear the axles :thumbsup:



.

[Superkirby]

Now see, that sounds expensive.

[Mudderoy]

Now see, that sounds expensive.

Yes it is. I spent $500 for the parts and (if I hadn't worked out a deal) it would have been about $300 for each axle, so another $600.

My gas mileage increased by 2 mpg though.

[Superkirby]

It would take awhile for the 2 mpg to pay for itself at $1100 to swap gears. What I would really like to do - and from what I can tell it would cost the same or could maybe be done for a little less - is to swap for a manual transmission. But right now I don't really see that happening either.

[Mudderoy]

It would take awhile for the 2 mpg to pay for itself at $1100 to swap gears. What I would really like to do - and from what I can tell it would cost the same or could maybe be done for a little less - is to swap for a manual transmission. But right now I don't really see that happening either.

Yep you could do that too. There are several ways you can fix the problem. Another set of wheels and tires. It's like everything else. What is it worth to you to fix the problem. Some people just live with it. I know this from daily driver, to hitting the trail. I love my 4.56 gears. It is hands down the best thing I've done to the Jeep that you can't see. ;)

[BlueXJ]

Your problem has a simple cure. It may sound strange but if you replacee your TPS and calibrate it your problem will go away. Fixed for under 100 bucks.
What is happening is the torque converter is locking and unlocking due to the signal from the worn TPS which feeds a signal to the transmission. Change and calibrate the TPS and your problem is gone.

[Superkirby]

First off, how do you calibrate a TPS? I thought they were all pretty much plug and play? And second, what do you think the chances are that a TPS is really the problem? It looks like a new one is $35. If I can spend $35 and my transmission shifts a little sooner thus improving my gas mileage, that seems like money well spent.

[adiga101]

how do you calibrate a TPS ????
please help

[Mudderoy]

I've never done this, as I have two 97+ XJs and they don't require it but I did find this...



http://z.about.com/d/autorepair/1/0/1/H/42197099.gif

Turn the ignition switch to the ON position.
Find the Four-way TPS connector and insert the black lead of the voltmeter into the back side of terminal (D). Insert the red lead of the voltmeter into the back side of terminal (A). Make sure that the throttle plate is completely closed against the throttle stop. Note the voltage reading of the voltmeter as it is connected across these two terminals, this reading is the input voltage.
Remove the red lead of the voltmeter from the back side of terminal (A) and reinstall it into the back side of terminal (B). Make sure that the throttle plate is completely closed against the throttle stop. Note the voltage reading of the voltmeter as it is connected across terminals (B) and (D), this reading is the output voltage.

continues...


:link: (http://autorepair.about.com/library/a/1i/bl232i.htm)

[Superkirby]

Thank you very much for that link. I will try that. I went to work this morning and all was well. Stopped at a stop light about 10 miles from work, and after that it wants to shift even later. Before it was shift at about 25 mph and again about 45 mph. The rest of the way to work and then again the whole way home it's shifting closer to ~30 and not going to 3rd until almost 55. I'm almost worried it's going to do damage if I don't get this figured out soon. So hopefully I can get it fixed. It's really bothering me.

[Superkirby]

I just went out to try this. My connector is different. The one in the link is for an 89. Of course they would change it. Currently still looking around trying to figure it out. If anyone has any idea how to test this I'd appreciate it.

[adiga101]

thank you very much :))
thanks all :))

[adiga101]

The input is 4.7 the out put was 4.6
i move it slowly the out put now is 4.2
is it good ???? please help

[Superkirby]

Not an expert but I'm going to guess no. From what I could tell in searching before I replaced mine, it should be a smooth transition from around 5 to almost 0. If you aren't getting any change I would guess it's bad. Mine was $35 for a 93, so I figured it was worth the money to check it.
Hope that helps.