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AW4 (Auto) transmission slipping, no torque

Pioneer89XJ

NAXJA Forum User
Location
Louisville, KY
Like the subject line states. Feels like a bad clutch on a manual transmission. If I hit the gas the engine revs but the rig does not pick up much speed. Seems to be going through the gears if you baby it. 168,000 miles on motor and transmission. Fluid level is fine. I did notice that the fluid didn't seem very hot when I checked it with my fingers after driving it for several miles. I pulled the fluid in the pan and added three new quarts, no change. The filter was changed 15,000 miles ago. I have changed the fluild in the pan every 10,000 miles for the past 30,000 miles I have owned this XJ. Any suggestions? Thanks.
 
I have a suggestion, take your XJ to the dealer or one of those quick change lube places that has the transmission fluid transfusion machine.

I know it like $80 at Jiffy lube and my dealer charges $150 but you may have bad fluid in your transmission and adding new fluid not getting rid of the "bad".

I know a few people at work who have have this done and they report it "made it like new".

I had put in Mobil 1 ATF and my AW4 did not like it. I lost 3 mpg because of it. I had the transfusion done to get all the synthetic out of the transmission & torque converter. My dealer added an addative to the transmission then let it come to temp. After it was at temp then he hooked up the machine and did the fluid exchange.

My dealer mechanic is sold on the transfusion machine, especially the addative. He owns a mid 80s Ford F-150 he did it. He was ready to do a rebuild and thought he'd try the transfusion first. He told me "it saved me a rebuild".

He told me mine came out pretty clean. then a few months later I was in there just talking to the mechanic. He told me about another 88 XJ he did the transfusion on and the stuff came out dirty, he never seen it that dirty.

I went to the dealer since there is a 12 month/12,000 warranty. Figure if transmission problems came up, which they have not, I could get them to fix it.

Also in the late 80s there was a TSB telling to only used Dextron with the certification number printed on the bottle. It is a number that begins with "D". I hope the ATF you have been using does have the cert number on the bottle.

It sounds like you have been doing good maintenace. You could have a worn out torque converter. Do you ever tow in overdrive? I had a coworker trash his converter towing in OD.

HTH

Martin
 
Thanks for all the ideas Martin. I have never towed in overdrive, btw. Does anyone now how hot the fluid should be to the touch after ten or fifteen minutes of driving? The fluid in mine doesn't feel very hot. Could this be a transmission pump problem?
 
:flame::flame:HARNESSING THE POWERS OF THE NECRONOMICON I COMMAND THEE TO RISE FROM THE DEAD AND BE DISCUSSED ONCE AGAIN MWAHAHAHA!!!!!:flame::flame:

Well anyway sorry to make my first post a resurrection but this is the closest matching description I've ever heard to the problem I'm having.

My 2000 XJ has 150k on the motor and transmission. I had some 31" M/T put on a few weeks ago and now what I can only describe as slipping and vibrating is happening in 1st off the line or if I floor it merging onto a freeway or something of that nature. The transmission was serviced about 20k ago and today I drained out the fluid and replaced it with Dex III. The Transmission shifts like a dream now but I'm still getting the described symptoms.

I see the OP in this thread ended up having a clogged cat but my motor is running great, recently passed smog with no issues and has the same power it had when I bought it in 2002 with 40k on it.

I almost never tow with it although I do take it wheeling now and then.

I've posted this up in several other forums to no avail. Hopefully you guys can point me in the right direction.
 
:flame::flame:HARNESSING THE POWERS OF THE NECRONOMICON I COMMAND THEE TO RISE FROM THE DEAD AND BE DISCUSSED ONCE AGAIN MWAHAHAHA!!!!!:flame::flame:

Well anyway sorry to make my first post a resurrection but this is the closest matching description I've ever heard to the problem I'm having.

My 2000 XJ has 150k on the motor and transmission. I had some 31" M/T put on a few weeks ago and now what I can only describe as slipping and vibrating is happening in 1st off the line or if I floor it merging onto a freeway or something of that nature. The transmission was serviced about 20k ago and today I drained out the fluid and replaced it with Dex III. The Transmission shifts like a dream now but I'm still getting the described symptoms.

I see the OP in this thread ended up having a clogged cat but my motor is running great, recently passed smog with no issues and has the same power it had when I bought it in 2002 with 40k on it.

I almost never tow with it although I do take it wheeling now and then.

I've posted this up in several other forums to no avail. Hopefully you guys can point me in the right direction.

Unplug the transmission control unit (used to be under dash by glove box but late models someone said it is on driver's side) and drive it, shifting manually. If the problem disappears, your problem is electronic.
 
Can you describe what this looks like?

Better than that. eBay, search "jeep cherokee transmission control module".

And it is a few inches from the steering column, driver's side, behind the knee panel.
 
yup. 97+ it's roughly above the gas pedal, under the dash. pre-97 it's under the paneling below the glove box. I believe on a few it was under the driver's seat (or was that the airbag controller?) until there was a TSB that moved it to avoid corrosion. Could be wrong on that though.
 
Cool. I found the image and I'll try that in the morning. If that's not the problem any ideas? Heck if it IS the problem what do I do? Switch out the module? Update the firmware somehow?
 
If manual works try another module next would be a wiring issue. When you figure out how to modify the firmware let us know it could be helpful.
 
Somehow I doubt I can just plug a usb cable into it.

He was just pulling your leg on the firmware.

IF it shifts normally manually, then the problem is electrical, i.e., no power to the TCU/TCM, bad wiring to/from the TCU/TCM, or bad solenoids in the transmission itself.

IF IT DOESN'T shift normally manually, then the problem is hydraulic or mechanical within the transmission, or with the inputs to the ECU/PCM/TCU/TCM--throttle position sensor is common, so is an out of adjustment throttle body cable (not a kickdown cable).
 
OK so I tried this and it did seem to fix the problem, BUT when I plugged it back in it seems to be shifting a TON better and not doing the slipping vibrating thing. I drove around town in stop and go traffic for 45 minutes to make sure everything heated up.

I'm wondering if the new tranny fluid just needed time to mix in? It only took 3 quarts. Also I sea foamed the engine yesterday maybe it was an engine problem after all?

thoughts?
 
Well, if the engine was running extremely poor, then some of the sensors would be sending wacko data to the transmission and engine control modules.

Just glad it is back in the running for you.
 
Well, if the engine was running extremely poor, then some of the sensors would be sending wacko data to the transmission and engine control modules.

Just glad it is back in the running for you.

I sure hope so. I'm going to keep an eye on things and if the problem comes back I'll let you guys know. Thanks for the help. I never would have thought of trying that on my own.
 
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