Aw4 Getting hot

If the pan is hot but the cooling lines are cold there is something not allowing the hot fluid from going through the cooler. Check the lines for kinks, also the rubber lines could have deteriorated & collapsed inside. That's where I would start.

check to see if the passenger side upper control arm didnt crush the lines.

If the trans fluid was boiling it should be overflowing out of the vent at the top of the trans.

Unless it is really low in the first place.

OMG after posting earlier I disconnected both trans lines and the factory cooler was completely blocked(could not blow through with 125 psi). So I bypassed the cooler with a line and now my gauge is reading, on level road at 55 it runs about 190 and when going up a hill it runs 220-230 and once it gets up that high it takes forever for it to cool back down to 200 and that is where it stays. Will the absence of a cooler make that much of a difference(it is 45* here)? I didnt put a gauge in it until I had the first overheating problem so I dont have a reference, but this seems too hot. I am going to install an external cooler tomorrow (I am going to convert the ac condensor into a trans cooler after flushing it). The trans shifts fine and everything works well, hopefully it will be alright. Any input is appreciated. thanks seth

sidssm said:

OMG after posting earlier I disconnected both trans lines and the factory cooler was completely blocked(could not blow through with 125 psi). So I bypassed the cooler with a line and now my gauge is reading, on level road at 55 it runs about 190 and when going up a hill it runs 220-230 and once it gets up that high it takes forever for it to cool back down to 200 and that is where it stays. Will the absence of a cooler make that much of a difference(it is 45* here)? I didnt put a gauge in it until I had the first overheating problem so I dont have a reference, but this seems too hot. I am going to install an external cooler tomorrow (I am going to convert the ac condensor into a trans cooler after flushing it). The trans shifts fine and everything works well, hopefully it will be alright. Any input is appreciated. thanks seth

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put a screen in front of it, in my neck of the woods, flyind debris or sticks easily puncture the condenser

Please whatever you do change the fluid asap!!

That's definitely too hot and the fluid is probably toast. The life of the fluid starts dropping off prety quick above 180*. One disadvantage of using just an external cooler (not sure how great the a/c cooler will be) is that it doesn't help the tranny get up to temp like the cooler in the radiator does. Might not be an issue in KY though.

What year? If it's over 150k on the rad it's probably partially plugged as well. Radiatorbarn.com or dpgoffroad both sell decent all-metal CSF brand for around $140 shipped.

From what I have read, it is my understanding that the correct temp range for tranny fluid at opertating temp is 200-230....so I am guessing it leaves the tranny at 220 or maybe higher if you are towing...goes through the factory cooler, which has coolant running around 210 or higher, and cools down to 215 or lower before returning to the tranny...unless you run it through another auxillary cooler to cool it down even more...

but then again I have read that the life expectancy of tranny fluid is 100,000 miles at 175*F so things must be running cooler than I thought....

The "oem" method of running the lines is......aux cooler first, then through the radiator.

That way it can't be overcooled. If it gets overcooled in the aux cooler, it will be warmed up in the radiator.

That's for a mid to cold climate.

In a hot climate you can do it differently since you don't have cold temps to worry about.

lawsoncl said:

That's definitely too hot and the fluid is probably toast. The life of the fluid starts dropping off prety quick above 180*. One disadvantage of using just an external cooler (not sure how great the a/c cooler will be) is that it doesn't help the tranny get up to temp like the cooler in the radiator does. Might not be an issue in KY though.

What year? If it's over 150k on the rad it's probably partially plugged as well. Radiatorbarn.com or dpgoffroad both sell decent all-metal CSF brand for around $140 shipped.

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Jeep is a 1989 143k miles but radiator was replaced 8 years ago at 100k(converted to open system).
A friend has his ac condensor converted to trans cooler and his trans pan stays cool all of the time(to the touch he doesnt have a temp gauge).
What happens if the trans doesnt run warm? (what happens when trans runs too cool)

anybody? bump