Transmission wont shift and serious loss of power
 

I have a 1995 jeep cherokee automatic. I all of a sudden started having problems where it did not want to shift while on flat land or going up hill. Downhill would shift normally. I checked the trans fluid and it was low. I filled up the fluid with the correct atf+4 and it got worse. Now it wont shift out of first. What could this be? I didnt flush the whole system after reading that completly flushing may do more harm than good and i also didnt change the filter obviously. I cannot get the RPM's over like 2,000 while going on flat or up hill. Down hill the RPM will go up but wont shift and i have a serious loss of power. 157xxx miles. Any insight will help, thank you

Now a 95 Cherokee has the AW4 yes? Dex/Merc is the correct fluid if I am not mistaken.

^^^What he said...
ATF4 is the wrong fluid. Now you don't really have a choice but to flush the system. FWIW - Changing the filter will not hurt the transmission no matter how many miles you have.

I think you may have a shift solenoid issue. There are 2 of these located inside the transmission pan, and are controlled electrically.

Try to see if you can manually shift your trans. If you can, it probably is a solenoid. (Shift it into 1-2 & see if it gets going from a stop easier)

If you google "AW4 solenoid replacement" there are tons of links.

The one in my 98XJ sometimes acts up when it gets really hot. I can manually shift it, until it cools down again. I need to replace mine at some point.

Gotta rule the throttle position sensor in or out early in ANY shifting issue. More on it below and how to test.
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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.

I tried looking into which fluid and everything said atf+4. When i added the atf+4 it got worse. I actually tried starting in 1-2 and it does the same, still have no power

Yes is a aw4

I had this conversation with Autozone when changing my filter. I argued with them for 30 minutes that I needed dextron and they kept saying no chrysler takes atf blah blah. Finally they looked it up because I was hell bent on using dextron and it says dex/merc on their computers. It is most definitely a dextron using transmission

Haha, well im not sure what to do. I also had a feeling it was a solenoid when i was looking into what it could be but what would explain the serious loss of power? Say the solenoid is the issue would it than be that when the trans solenoid went bad it set the computer in limp mode? The motor is also very loud, it just sounds so tired and right before this happened it ran great and had no shifting issues either.

Is your check engine light on? Regardless of this fact, have you tried checking the codes yourself? Did you try 'manually' shifting as suggested above to try and rule out the solenoid?

Follow this link passed on to me by others in this forum.
http://www.go.jeep-xj.info/HowtoECUcodes.htm

I know ignition issues can make you shift pretty funky, but it'd have to be running pretty bad to cause it to not even leave first. I would defiantly change that fluid and transmission filter as soon as possible and try the dropping it into 1st and up shifting yourself. Also, why was your fluid low? Do you have leaks? where from and how bad?

Try unplugging the battery for about 30 minutes or so, go watch some tv. Come back later and hook it back up and stay in Park. Does it run rough just sitting in park after unhooking the battery for awhile? Did it before?

First thing I would do is fine the 2 connectors that carry all the signals between the TCU, speed sensor, TPS, solenoids etc and unplug them and spray them out with electrical cleaner. They're located near the trans dipstick tube. One is gray , the other black. They get corroded inside.

Check engine light came on a couple times but that was before the whole shifting issue. It has not come back since. I must have a slow leak somewhere. I wanted to see if i could possibly drive it to advanced to have it checked with their scanner but because i put the atf+4 in would this completly ruin the transmission by driving with the wrong fluid? It does not idle rough at all and has never stalled out on me. Starting in 1-2 is the same as starting in D, 1-2 makes it no easier. It doesnt have problems initially getting itself going its once i get up to around 2000rpm thats when the rpm wont go up any more unless going downhill and even then it doesnt want to shift

Ive never had any spots on the ground from where its leaking, pretty much the whole front of the jeep is wet from fluid.

Do i need to completly flush the system since i added 2 quarts of atf+4 or will dropping the pan be fine?

"Can't get above 2000 RPM" - could be engine problem, tranny won't upshift when it thinks engine is working really hard (via kickdown cable).
Check if your catalytic converter is plugged, causing engine to have to work really hard. Easy to do: remove the front O2 sensor from the exhaust pipe, and take her for a spin. If it sounds like a jet taking off when you step into it, and you have power again, the cat is plugged.

My cat is shot, its been shot since i bought it, it makes a loud clanking noise, the heat shield is almost completly gone, i wonder if maybe the packing inside is broken and clogging it it up, i also have strong smells of gas while vehicle is running and a little while after i turn it off. I will check that hopefully today. If this is the case would the check engine always be on because i have no check engine light on, just a couple times before when i was doing highway driving

Where would the o2 sensor be? Am i looking under the hood or under the vehicle?

Also ever since ive had it when i put it into gear it clunks and jerks the vehicle a little bit, almost like vehicles do when parked on a hill

Mine had the same problem and was the tps. Try unplugging the trans control fuse under the hood and manually shifting and if it shifts fine its electrical and not mechanical problem.

Sat in park and revved the engine and i get to about 3100-3200rpm and it starts to drop a little while keeping same pressure on gas and it almost sounds like its having trouble breathing

You get at the O2 sensor from underneath. It's about the size of a sparkplug (maybe a little bigger), screwed into the exhaust pipe just where the pipe comes down from the exhaust manifold.

Ok, i didnt unscrew it yet but i realized my down pipe also has a good size dent in it which prolly isnt helping any..

That dent is there from the factory; not to worry.

O ok, thats kind of odd

I just fixed my tranny issue with a new TPS.

bad u joint in the driveshaft.

It turned out to be a clogged cat and in need of a tune up, thanks for everyones help

power loss / not shifting
 

I had the same symptoms (power loss / not shifting). Turned out to be a clogged cat and a faulty neutral safety switch.

But is it not shifting into drive or wen driving

Mine didn't want to shift either. If you mashed the gas pedal while going down the road, it would bog instead of downshifting. It also sometimes wouldn't upshift into 3rd or overdrive.

So how did u fix ur problem

Clogged exhaust system... parts of the converter and muffler had collapsed, restricting the flow severely. Also changed the o2 sensor in the cat, and disconnected the battery to reset the computer.

I know my cat is loose inside i need to get ride of it for sure

So you've got a loose cat inside your Jeep. Hope you have a litter box.

cat in car
 

:laughing: I was forced to haul my daughter's cat about 1500 miles when we moved. I'm not sure who wanted out of the car worse at the end of the trip! But that is definitely on my "NEVER AGAIN!!!" list.....