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Drives by Braille
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Discussion Starter #1
Heading to work today I got another check engine light, same as before, P0740. TCC Malfunction/Slip.... so I crawled under it durring my lunch break and noticed that the front part of the trans cooler line(pressure side) was leaking, not a lot because this is the fisrt I've noticed. And last time this code popped up it was a little more than half a quart low. So I think thats where the fluid was going. Its still pretty clean under there so it hasn't been leaking long, and might only be when its driving(being under pressure).


So I'm wondering if the loss of fluid and loss in pressure in the line would cause the code to pop up?

Also... should I just replace the lines? Or go with a stand alone external trans cooler? Got any brand suggestions? I found the lines assembly for $60 shipped off eBay.... the local dealer says they don't stock them any more :rolleyes:

So what you do or think would be the best? THANKS! :cool:
 

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well the tranny oil cooler is just a part of the radiator so if its there than i wouldnt bother with stand alone. I'm guessing the hose is all old and ripped so it leaks.. I would replace the hose and see if leaks then... I would think loss of pressure would kick a code but i dont have much experience with jeep autos
 

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Drives by Braille
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Discussion Starter #3
The only problem with the cooler being built into the rad is that it passes with the hot coolant for the motor keeping the trans fluid warm, but if it was seperate it would be a lot cooler.
 

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WINNAR!!!!!!
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While I do agree that if it is separate it will run cooler but the tranny cooler is its own system inside the radiator. It passes through its own set of tubes passing across the fan before heading back to the tranny. But how do you know where your tranny temps operate now??

Without a decent inline temp sensor it really is just a guesstimate. I had the option of running my auto swap to a 3 row HD radiator. I chose to run a separate cooler with a fan. I'm going to run a thermostat setup to kick the fan on and off automatically with a kill switch on the dash.

I chose this unit from derale.



It is a little pricey at 150 bucks but I shouldn't ever have to worry about cooling my tranny. You can get it at summit.
 

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Clifford whats wrong with that picture?

no mud in it :)

That does look good though. The radiator is seperated into 2 so the tranny oil does not pass by the coolant fluid. They are seperated and arent crossed or anything... I'm guessing the rad is like this on wranglers (bellow). Basically all i'm trying to say is if it isn't broken dont fix it theory unles you have to upgrade.
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TCC Slip is could be caused by a few things. One of the #1 things that will cause it is having stock gears and letting it "lug" while driving around in low speeds. A low fluid will also cause this code to show, but may not mean a Converter failure. I would remove the lines from the cooler in the trans and just add a cooler in front of the radiator. remember, fluid in the radiator cooler is going to be AT LEAST 210 degrees!!! Its too hot!! Here in AZ you will see trans temps over 250 if you have a lifted/big tire jeep with no gears, and its 100+ outside. Get an aux cooler, and mount it in front where it can get LOTS of air. Keep that trans under 200 degrees if at all possible. When ATF gets hot, it will start to foam and loose its lubrication properties, therefore causing a loss of pressure ( foaming ATF is airy, and air wont move hyd solonoids that keep pressure on the bands in the transmission) and will cause slip.

Joe


Heading to work today I got another check engine light, same as before, P0740. TCC Malfunction/Slip.... so I crawled under it durring my lunch break and noticed that the front part of the trans cooler line(pressure side) was leaking, not a lot because this is the fisrt I've noticed. And last time this code popped up it was a little more than half a quart low. So I think thats where the fluid was going. Its still pretty clean under there so it hasn't been leaking long, and might only be when its driving(being under pressure).


So I'm wondering if the loss of fluid and loss in pressure in the line would cause the code to pop up?

Also... should I just replace the lines? Or go with a stand alone external trans cooler? Got any brand suggestions? I found the lines assembly for $60 shipped off eBay.... the local dealer says they don't stock them any more :rolleyes:

So what you do or think would be the best? THANKS! :cool:
 

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Drives by Braille
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13,642 Posts
Discussion Starter #7
TCC Slip is could be caused by a few things. One of the #1 things that will cause it is having stock gears and letting it "lug" while driving around in low speeds. A low fluid will also cause this code to show, but may not mean a Converter failure.
What exactly do you mean by "lug"? I was doing about 55-60 when the light has come on, both times.

If I were to go with an external cooler, I would just use hose clamps right? I don't need any pressed on lines or anything?

The only replacement that I have seen offered are 2 pieces of rubber trans line with clamps on the ends that would replace the rubber sections in the stock lines.

Thanks for the info Joe :cool:
 

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WINNAR!!!!!!
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What exactly do you mean by "lug"? I was doing about 55-60 when the light has come on, both times.

If I were to go with an external cooler, I would just use hose clamps right? I don't need any pressed on lines or anything?

The only replacement that I have seen offered are 2 pieces of rubber trans line with clamps on the ends that would replace the rubber sections in the stock lines.

Thanks for the info Joe :cool:

anytime you ask someone in that business about hose clamps they will all tell you it is hack. There are much better ways to go about installing a cooler.

I plan to use push lock fittings that screw into both the tranny and cooler. Locally I found the low pressure hose for around 1.30/ft. You shouldn't need more than 10 feet or so depending on where you mount the cooler. The fittings are not all that expensive in comparison to some other parts you buy. I figure I will have around 200 installed for the complete setup minus the temp gauge.
 

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well the tranny oil cooler is just a part of the radiator so if its there than i wouldnt bother with stand alone. I'm guessing the hose is all old and ripped so it leaks.. I would replace the hose and see if leaks then... I would think loss of pressure would kick a code but i dont have much experience with jeep autos
what AZtj said ... and the fact taht the tranny cooler for a TJ is SEVERELY undersized for our application ... i have to let the tranny cool down for an hour and then reset the computer every time i wheel my TJ
 

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Jack Lives Here!!!
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In general the stock TJ tranny cooler does fine. However out here in the desert conditions we should be running stand alone coolers for extended periods of summer wheeling. I still need to do this myself and it's on the I'm gonna do it before it gets really hot list. :D
 

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Drives by Braille
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Discussion Starter #12
Better Hurry! lol

I'm thinking of just cutting the stock lines with some compression fittings now and running a stand alone cooler in the front of the rad. I'll just have to keep an eye on the fluid level untill I can get this done next weekend(maybe).
 

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Affende i should be lucky that i wanted a manual then :)
you have no idea.

as soon as i get the fullwidths under the jeep on 4 links with coilovers ... im am swapping in an AX15 to get rid of this hunk of junk they call a Chrysler 999
 

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Drives by Braille
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Discussion Starter #14
^ why not an AW4? I plan on that later next year, if this one survives lol
 

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^ why not an AW4? I plan on that later next year, if this one survives lol
i dont want to deal with an auto tranny ... they are too much a pain the butt ... not to mention the fact that i burn up the clutches about every 60k if not less .... 1 big clutch is easier to change out than 20 small ones IMO
 
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