AW-4 Tranny question

[dagod16]

Tranny question,

I have 201,000 miles on this original AW4 tranny. I feel like the tranny has trouble shifting at time at shift points. For example the first shift point it seems to hesitate ever so slightly. Tranny fluid is changed every 45 K and the fluid is slightly brown but the next fluid and filter change is in 20K. It also seems to shift at a higher rpm and I adjusted the shift rpm/ gas pedal cable dohicky under the hood and it's set correctly. I really think it will last another year or two but I am just wondering.

The jeep warms up 10 min each morning before I drive it.

Maybe I should take it in and have the fluid and filter changed again.

It runs fine but I just feel like it has troubles shifting at times which is not even much of a big deal.

Actually when it has trouble it will hold at the shift point and rev(rpm) a bit higher for one second or less. Almost nothing


But I'm curious.

Your thoughts.

Thanks

Everyone.

[ArmyGuy45]

Tranny question,

I have 201,000 miles on this original AW4 tranny. I feel like the tranny has trouble shifting at time at shift points. For example the first shift point it seems to hesitate ever so slightly. Tranny fluid is changed every 45 K and the fluid is slightly brown but the next fluid and filter change is in 20K. It also seems to shift at a higher rpm and I adjusted the shift rpm/ gas pedal cable dohicky under the hood and it's set correctly. I really think it will last another year or two but I am just wondering.

The jeep warms up 10 min each morning before I drive it.

Maybe I should take it in and have the fluid and filter changed again.

It runs fine but I just feel like it has troubles shifting at times which is not even much of a big deal.

Actually when it has trouble it will hold at the shift point and rev(rpm) a bit higher for one second or less. Almost nothing


But I'm curious.

Your thoughts.

Thanks

Everyone.


Does the fluid smell burnt? If so, changing the fluid will be a gamble to get more miles out of it or not.

[dagod16]

Do I smell it hot or cold?

[dagod16]

The tranny shop drove it and they think nothing is wrong with it. But I am anal about the sounds, feel, bumps, hickups, and shakes on my jeep so I notice any little thing.

[ArmyGuy45]

I would check both hot and cold for smell but only check hot for correct fluid level.

[dagod16]

Doesn't smell burnt, just the normal tranny smell.

Maybe come summer time I will have it changed.

[dagod16]

Does the AW4 have a shifting solenoid or something to help it shift that would be an easy fix when the pan is down?

[ArmyGuy45]

Does the AW4 have a shifting solenoid or something to help it shift that would be an easy fix when the pan is down?

Yes, and you can measure the resistance to see if they are working properly.


This may help. :link: (http://www.xjtalk.com/showthread.php?t=6372&highlight=solenoid)

[dagod16]

Is that solemoid inside or outside of the tranny.

[Mudderoy]

Is that solemoid inside or outside of the tranny.

Inside, you can see them when you drop the pan and filter.

[dagod16]

Is this solenoid like a plug in type thing? Ya know pull old of out
then push in new one.
will my tranny shop know the resistance?
Is it expensive to do during a fluid change?
How often do they go bad?

[4.3LXJ]

Easy to replace once the pan is dropped. But if it shifts, I don't think that is the problem

[dagod16]

It shifts fine. It just hesitates a sliver at certsin shift points esp when cold.

[lthamm]

Have you put a tester on your TPS make sure the outputs correct

[Brasscatz]

just for poops and giggles, try adjusting your kickdown cable.

The youtube video on this is private now, so if you need pointers I can go outside and video it for ya on mine.

[dagod16]

How do I test the tps

[Brasscatz]

Taken from this link: http://www.jeepforum.com/forum/f11/how-test-tps-610386/


TPS TESTING

You may have one or more of these Physical Symptoms:

1) The engine loses power and is stalling.
2) The engine will idle, but may die as soon as you press the gas pedal. When driving, it seems as if all power is gone.
3) Sometimes it feels as if the transmission is failed or isn't shifting properly, if at all. If you quickly jump on the gas you might be able to get the transmission to shift, but it won’t shift properly by itself. Shifting manually, the transmission goes through all the gears.

NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics. The TPS function should be verified early in the troubleshooting process, when a transmission issue is suspected.

TPS TEST

You should have 5 volts going into the Throttle Position Sensor (TPS). It is best to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. At idle, TPS output voltage should be greater than .26 volts but less than .95 volts. Move the throttle and look for smooth meter response up to the 4.49 at WOT. The other wire will be the ground and should show no voltage.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.


The TPS is sensitive to heat, moisture, and vibration, leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following:

-Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".

- High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.

-Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.

-Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted accordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.

- Engine Misfire: A faulty TPS can report values outside the acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessive misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.