Mr.JayDeeM

I took my gf out to do some small wheeling. Keep in mind, my transmission was acting perfectly fine day before. I went to a spot where it have few creek water crossing and only really huge water crossing was high up to my bottom of the doors with my 2 inch lift. After when we were done wheeling, it took about 3 hours to get through the trails we were on.

Well, as we were heading home on the highway going around 72 mph, it would shift back and forth to 3rd gear and leave me running 3k rpm at 70mph. Then I had to manually shift it into 3 then od, then it would be fine for another 5 minutes and it start all over. There's some burning smell to it too, I figured from shifting too much. I also checked my fuild level in neutral while running as well. Fuild looks fine, not bright red but then again its hot. I will check again tomorrow to see what color it is.

I know AW4 are pretty much bulletproof but do they not like to be smeraged in water? Even then how would the water get in if that the case?

I read online that the solenoids are prob bad?

Any advice? I know alot more about manuals than I do with automatics....

peep

Any indication that the trans took in some water? What about the differentials?
Fluids changes are real cheap compared to mechanical parts. Consider thorough checks and changes after high water exposures. Are the rear drums packed with mud causing some of the burning smell or extra driveline load, braking ok?
Give her systems a thorough inspection.

Mr.JayDeeM

The brakes are fine. I didnt go through any real heavy mud. I know the diffs oil will be changed here soon. I might go ahead and change transmission fiuld and see what it does. My next question would be how would water get through in the transmission? I don't have any oil leaks prior wheeling. How would I check for water in the transmission by looking at the dip stick?

EastBeast

There is a breather for the aw4 on top of it. It doesn't have a hose that runs up high so if you put the tranny underwater it's quite possible it got some in it. This thread has a picture of it: http://www.naxja.org/forum/showthread.php?t=1064881

Mr.JayDeeM

I see that now. It calling for a fluid change and go from there. What type should I go with? ATF4 or dex/merc?

EastBeast

aw4's take dex/mercon.

tjwalker

Yes, use Dex/Merc III compatible fluid.

For your issue, you MUST rule a faulty throttle position sensor in or out early in the troubleshooting process. The TPS is directly involved in shifting characteristics of the AW4 transmission. Oh, and then there is this about the TPS: THEY HATE WATER! Test and or replace it before looking elsewhere; my gut instinct is that this could be the culprit here after your water crossing.
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is 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. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

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: -

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

• 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 acordingly 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 fault TPS can report values outside the deined acceptable range causing the ECU to incorrectly fuel the engine. This is noticable 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 excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.

peep

That is one of the most straight forward information presentations on the TPS function and cause/effect relationships I have seen presented. Thank you TJW! Putting this one in my favorites list for reference.

Mr.JayDeeM

I understand it could be my tps, and its on the throttle body. But, the water crossing I went into was never high enough to go over my hood tho.

Mr.JayDeeM

Well, this morning I went out to check my cold level trans fuild, before I start it up, I checked the dip stick, it was full, then I started it up while it running in neutral, the level went all the way down to where it says add. Is that could be my problem?

tjwalker

The TPS doesn't have to be immersed in water to fail. Just needs a little water intrusion. Don't rule it out!

Tranny fluid should always be checked with a HOT engine, flat surface, transmission fully exercised. Don't ever check it cold. Proper level on the dipstick is important. But be careful not to overfill; it's very easy to have that happen as adding a little fluid can bring the level up on the dipstick very quickly. Slow as she goes....

Mr.JayDeeM

Yeah, I checked it while it was hot and running in netural, its full and nice and red. I'll check the tps and clean it. Same thing for trans sensors.

mr baer

You might have over heated it.
Mine dropped 3rd and 4th on the way to a trail a while back going up some long hills, when I was going down the other side it cooled off and the gears came back. I had crimped the lines to my cooler closed cause the diff came up and hit them.

Mr.JayDeeM

Even on the highway on the way home going 70 mph would overheated it? It was somewhere around 30 degrees outside. I should try and drive it and see what it does this time?

TPS controls idle reading as well correct? Well, my idle is perfectly fine and engine runs very smooth.

tjwalker

The ONLY way you are going to rule out your TPS is to either test it or replace it. Get out the meter.