Im sure this question has been asked time and again but here goes.
I have a '93 XJ 4.0 4-speed auto trans. 186,000 miles. It shifts pretty rough, i.e. takes alot of RPM's for it to upshift. If I have the shifter in 3rd I can get it to go from 1-2, then when I put it into OD it will go into 3rd but wont go into 4th, I tried to drive it to work today and was turning 4000 RPM's at 55 MPH. It seems like it wants to upshift into 4th, but wont, I am going to change trans fluid and filter this weekend, for all I know the filter is gunked up and has not been changed in years. Previous owner said he checked the TV cable, though Im going to myself. Also my check engine light is on, I have two spare brain boxes. Any other thoughts on what it could be? Anything will be appreciated, thanks.

 

1. What is the COLOR of the transmission fluid?
2. Is the transmission fluid at the correct level on the dipstick with a hot engine, fully exercised transmission?
3. Does the transmission fluid smell burnt?

Answer all of the above for starters.................

But to add to fluid checks, the fact that you have both symptoms and a check engine light is not likely a coincidence.

The strategy for ANY check engine light is always the same. Retrieve codes. Only then can you decide how to attack the problem. Anything less is pure guesswork.

Here is how you do that on your 93. Very easy. Let us know what you find!
--------------------------------------------------------------------
Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995

1) Start engine (if possible). Move transmission shift lever
through all positions, ending in Park. Turn A/C switch on and then off
(if equipped).
2) Turn engine off. Without starting engine again, turn
ignition on, off, on, off and on within 5 seconds. Record 2-digit
fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash,
4-second pause, flash, flash, flash. After a slightly longer pause,
other codes stored are displayed in numerical order. When MIL begins
to flash fault codes, it cannot be stopped. Start over if count is
lost.

NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.

 

I'm not sure of your level of tinker-ability, but you can also check the shift solenoids... they should be in the range of 16Ω.... and you don't even have to drop the tran-pan. The tcu is located under the passenger side lower dash portion. Unplug it and check; I believe pin 14, 15 and 16. W/ the other lead connected to ground. Hopefully, someone can confirm the pins. There is also a website about the Cherokee tcu pinout; can't think of it off the top of my head. Good luck!

 

For my '97:
Trans Control Module (TCM) Harness Lock Facing Up
There are 26 cavities, two rows of 13.
Top Row, last 3 cavities on the right side
#11: Torque Converter Clutch. Wire: Dark Blue/White
#12. Shift Solenoid #1. Wire: White
#13. Shift Solenoid #2. Wire: Orange/White

Resistance should be between 11-15 ohms at the solenoid, this doesn't take into consideration the resistance in the meter's leads and the wires/connectors.

You can also check all three solenoid's resistance through the connection at the rear of the passenger side engine compartment near the firewall.

There are two connectors, they are either black and grey or both grey. Regardless of the color, one is an 8-way, the other a 6-way, you need to check the smaller one with a digital meter grounded at the negative battery post.


Again, this is for my '97. There may have been changes in the connectors because in 1997 the TCM has the ability to communicate with the PCM. The TCM also has the ability to monitor transmission faults which could affect emissions. Any fault which could affect emissions will set a code in the PCM and will illuminate the MIL.

 

Ok so I changed the fluid and filter, got her nice and warm and went on a test drive, shifts MUCH better, shifts all the way up to 4 just fine. So now onto something else (of course), there is now a strange knock, its not constant so I dont believe its something internal in the engine. Its just knocks a little here and there, engine oil is fine. I did not notice it before I changed the trans fluid and filter. Any thoughts on what it could be?.....I cant really describe it, just a strange knock sound, off and on. Oh, I will get to the fault codes soon enough, not enough hours in a weekend. Thanks.

 

Well so this morning I start the XJ before work, let her warm up about 10 min or so, pull out of the driveway and I run into the same problems, not shifting right.....yesterday right after the trans fluid and filter change it was fine. Maybe it needs to warm up longer? That doesnt really make any sense to me though, it has me baffled. Any thoughts on what would cause it to be fine one day, and not the next? Thanks

 

Next step absolutely is to pull the stored codes!! Use the technology provided to you by your Jeep. It's trying to tell you something.....

Here is how to do it on your 93. Takes all of 3 minutes.
------------------------------------------------------------------------------

Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995

1) Start engine (if possible). Move transmission shift lever
through all positions, ending in Park. Turn A/C switch on and then off
(if equipped).
2) Turn engine off. Without starting engine again, turn
ignition on, off, on, off and on within 5 seconds. Record 2-digit
fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash,
4-second pause, flash, flash, flash. After a slightly longer pause,
other codes stored are displayed in numerical order. When MIL begins
to flash fault codes, it cannot be stopped. Start over if count is
lost.
NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.

 

Ok so I pulled the codes when I got home from work and this is what I got....

36-Did not find a fault for this code

24-Throttle Position sensor voltage high or low. (I believe would explain the off and on "knocking" Im hearing)

I cannot find a fault for 36 though, I pulled the codes 3 different times to as to make sure I got it right. Anyone know what 36 might mean? Thanks

 

Here is the good news. Your code 24 directly matches up with your symptom.

Replace your throttle position sensor. The TPS is directly involved with shift points for the AW4 transmission. Don't buy a cheap one and don't buy anything off ebay unless brand name is confirmed. I buy and recommend Mopar throttle position sensors. Well worth the extra money.

This is not related to the "knocking" you are hearing. One thing at a time. Resolve the shifting issue; clear codes and then see where you're at.
-------------------------------------------------------------
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 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 fault TPS can report values outside the denied 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 excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.

 

Mr. Walker, thank you so much for all your help, here what I did...

I "backprobed" the TPS with my multimeter, it was giving me a reading of 4.58V from throttle closed to open, it should have changed throughout the entire range of motion correct? Thanks

 

TPS should show a smooth sweep of voltage from closed to fully open throttle. Really looks like yours is hosed.

The roadmap to follow for codes is always the same. Follow the codes. And that code and your testing leads you to a faulty TPS. I would also get a can of electrical contact cleaner (widely available, even at Walmart for only a few bucks) and when you are replacing it, thoroughly spray the connector for the TPS before you plug it into the new sensor. Never hurts to have a can of this on hand for sensor connectors. And I usually add a small dab of "dielectric grease" to that connector before reconnecting.

Good luck and keep us updated!

 

Ok so I went and got a new TPS, just went down to auto parts store, I know I should have gotten a OEM mopar part, but Im impatient and wanted to solve the problem as quickly as possible. So I put the new one in, started it up, let it warm up for about 10 min or so, brushed off the snow and took it on a test drive. Shifted wonderfully and the 'check engine' light is now off. Thanks for your help, now to try and resolve the knocking issue.

 

I to had issues with my AW4, after I changed the fluid and filter it seemed to shift to slow into 2nd and I thought that maybe I had damaged one of the shifting solenoids taking off or putting on the trans pan. But I came here as always and started searching found this thread and got to thinking that before I did the trans fluid and filter I put on an AirRaid throttle body spacer and that it was a little snug with the cable and wires. So I took it off and then took it for a drive, boom just like that perfect flawless shifting the way I like. I know I need to just adjust the tv cable and I can run the throttle body spacer, but knowing that its that and not the solenoids or worse puts me at ease!

Thanks guys