How to install a Derale 20561 transmission cooler on your Wrangler TJ

TexasTJ2004 said:
So heat up the tub?
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It's not the tub you're trying to cool, it's the aux transmission cooler you want to cool by drawing cooler air from the ground up through it. There's hot air above it from the muffler, engine, and especially the catalytic converter so don't be pulling air down from there through the aux cooler.
 
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Jerry Bransford said:
It's not the tub you're trying to cool, it's the aux transmission cooler you want to cool by drawing cooler air from the ground up through it. There's hot air above it from the muffler, engine, and especially the catalytic converter so don't be pulling air down from there through the aux cooler.
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I could be wrong but I think Texas was simply trying to confirm which direction the air should flow…not that he was trying to cool the tub.

Regardless I appreciate your explanation to double check that the cooler/fan orientation and fan wiring causes air to correctly be pulled up through the cooler (towards the tub). I was confused by different photos from folks bc it seems like ppl have oriented them in different ways. I’ll be installing it the way you described.
 
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Jerry Bransford said:
It's not the tub you're trying to cool, it's the aux transmission cooler you want to cool by drawing cooler air from the ground up through it. There's hot air above it from the muffler, engine, and especially the catalytic converter so don't be pulling air down from there through the aux cooler.
Click to expand...

Thanks for a detailed answer. I was indeed referring to byproduct of airflow being directed up and heating it up. However, you are right, that the tub is getting heated up so much by everything else, to level that that this AUX cooler does not really add to tub being heated.
 
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TexasTJ2004 said:
Thanks for a detailed answer. I was indeed referring to byproduct of airflow being directed up and heating it up. However, you are right, that the tub is getting heated up so much by everything else, to level that that this AUX cooler does not really add to tub being heated.
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It’s not generating enough heat to cause any issues otherwise the puller fan wouldn’t hold up…and it’s a steel tub which isn’t a great heat sink.

Imo, if the cooler causes problems by heating the tub, then your temp gauge will likely indicate a number higher than you want to see.
 
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Mikee024 said:
It’s not generating enough heat to cause any issues otherwise the puller fan wouldn’t hold up…and it’s a metal tub which isn’t a great heat sink.

Imo, if the cooler causes problems by heating the tub, then your temp gauge will likely indicate a number higher than you want to see.
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it does not cause any problems.
I have to say that I would not do trails in Texas heat w/o aux transmission cooler. It should come like that out of the factory.
 
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TexasTJ2004 said:
it does not cause any problems.
I have to say that I would not do trails in Texas heat w/o aux transmission cooler. It should come like that out of the factory.
Click to expand...

Did you install a lower-temp thermister for the electric fan? If so, what part did you choose?

I installed the Derale cooler after repurposing the Setrab cooler that’s in the grill.

Unfortunately, the Derale cooler is running the transmission hotter than it ran with the Setrab in the grill by 20*+. I initially thought the thermister was failing intermittently, but now I believe it simply doesn’t kick the fan on until my temp gauge shows about 199*, and then the fan is back off around 190* or so.

Also, my current thermister coupler points the thermister down towards the ground rather than up like I’ve seen in all other photos. I don’t know if a different coupler is or a different cooler would be required to fix that. I double checked the tightness of the fittings (I wouldn’t want them any looser or tighter).

IMG_6367.jpeg
 
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Mikee024 said:
Did you install a lower-temp thermister for the electric fan? If so, what part did you choose?
Click to expand...

I'd like to try a lower temp switch also.
Mine wasn't kicking on when I thought it should.
So I bypassed the thermal switch and turn it on manually when I see the temperature rising.
 
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LONGJP2 said:
I'd like to try a lower temp switch also.
Mine wasn't kicking on when I thought it should.
So I bypassed the thermal switch and turn it on manually when I see the temperature rising.
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Good to know yours came on late as well. I’m on hold with Summit right now to discuss thermister options.

I plan to install a manual cut off switch I have once the Derale proves itself, I but I’d prefer to have the system kick on automatically.
 
Mikee024 said:
Did you install a lower-temp thermister for the electric fan? If so, what part did you choose?

I installed the Derale cooler after repurposing the Setrab cooler that’s in the grill.

Unfortunately, the Derale cooler is running the transmission hotter than it ran with the Setrab in the grill by 20*+. I initially thought the thermister was failing intermittently, but now I believe it simply doesn’t kick the fan on until my temp gauge shows about 199*, and then the fan is back off around 190* or so.

Also, my current thermister coupler points the thermister down towards the ground rather than up like I’ve seen in all other photos. I don’t know if a different coupler is or a different cooler would be required to fix that. I double checked the tightness of the fittings (I wouldn’t want them any looser or tighter).

View attachment 448389
Click to expand...

I believe that your gauge is measuring based on pan or valve body.
The cooler thermal switch measures on return line from the radiator. This means that your gauge is 199F, but the radiator cools it down To under 180F and then the cooler does not activate.
I am planning to put a lower temp switch, specifically 140F on and 125F off. I expect it to keep the transmission at around 160F.
 
TexasTJ2004 said:
I believe that your gauge is measuring based on pan or valve body.
The cooler thermal switch measures on return line from the radiator. This means that your gauge is 199F, but the radiator cools it down To under 180F and then the cooler does not activate.
Click to expand...

I agree with that, but I know the Setrab kept things at 180* so I’d like for the switch to turn the fan on sooner than 200* at my guage. It’s hot in the desert and I haven’t done anything remotely taxing yet. I need the temps to be lower before I’ll trust this out in the rocks where it will surely be hotter if I leave things as is.

TexasTJ2004 said:
I am planning to put a lower temp switch, specifically 140F on and 125F off. I expect it to keep the transmission at around 160F.
Click to expand...

I’d like to find a switch that turns the fan on at 160* that way my gauge reads closer to 180*. I’m looking for a balance of not wanting the fan to be on too often (I want it to last) but I also want it to turn on sooner than it currently does.

do you know of any reputable thermisters that will work that I should check out?
 
LONGJP2 said:
Yes, the switch I use to turn the fan on is actually the switch I installed to turn it off.
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Oh yea I understand that your manual switch controls voltage to your fan.

I prefer to keep my set-up thermostatically switched but have voltage run through a switch so I can cut power off for future water crossings. I purchased the manual switch, but I’m holding off on that install until the Derale proves itself worthy of keeping.
 
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TexasTJ2004 said:
I am planning to put a lower temp switch, specifically 140F on and 125F off. I expect it to keep the transmission at around 160F.
Click to expand...

I wish mine worked that well.
I've never seen the temperature go down because of the fan.
Normally it stays at 180°, but air temperature and hills affect it the most.
I've even seen mine go to 215°-220° with the fan on.
This is usually on highway inclines, not crawling.
 
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Am I the only person running this kit with the thermostat pointing down at the ground? I double checked tightness.

IMG_6380.jpeg
 
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