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Auto Transmission Coolers

Yellow Cake Kid

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...I installed... ...one... ....It comes with a fan and keeps my temps well under 200...

...I put a stacked trans cooler on my jl. it made no difference... ...the trans, has a thermostat internal, so no matter what we do the thermostat will control...

These seem like two completely different experiences and conclusions.

The ambient air temperature gets really hot where I drive. I'd like to run an extra transmission cooler, if it would help keep my transmission cooler, so it would be nice to know what the options are for a Wrangler JL 3.6L system.

Thank you.
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oscarvan

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What does Jeep say is the proper operating temperature for this unit? What people "think" matters not. Manufacturers specs matter. Example Allison says it's normal for the 2500 installed in my motorhome to operate between 200-230 in the summer mountains. And, it all depends on where the sensor is located. Converter output temp CAN reach 300ºF. Most transmissions send oil pan temperature. Again, in my case 240-260 is the limit........
 

Powerwagon1

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What does Jeep say is the proper operating temperature for this unit? What people "think" matters not. Manufacturers specs matter. Example Allison says it's normal for the 2500 installed in my motorhome to operate between 200-230 in the summer mountains. And, it all depends on where the sensor is located. Converter output temp CAN reach 300ºF. Most transmissions send oil pan temperature. Again, in my case 240-260 is the limit........
I have had transmissions with remote coolers run at 175 and have a long life (over 200,000 mi. ) in many vehicles. I "think" heat is the enemy of any auto trans. fluid and I try to keep mine as cool as possible within reason.
I'm sure the Allison could double this mileage without additional cooling but I bet if you added one you would see a difference . IMHO
 

Powerwagon1

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heamick said:
...I put a stacked trans cooler on my jl. it made no difference... ...the trans, has a thermostat internal, so no matter what we do the thermostat will control...

One would have to get around that first, Possibly bypass that if possible. When mine runs out of warranty that will be on the Mod List for sure.
 

Yellow Cake Kid

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The question remains; does or does not adding an additional transmission cooler reduce the temperature seen at the transmission fluid temp sensor?

When I am gliding down a paved hill at 60mph on the way back to town my transmission temp drops from the 225*f range I see while wandering off road to a relatively cool 195*f, so it doesn't seem like the thermostat is preventing the cooling fluid from circulating and cooling down.

If I could keep it down near 200-210 at worst case, I'd like to do so.
 

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slater dennis

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The question remains; does or does not adding an additional transmission cooler reduce the temperature seen at the transmission fluid temp sensor?

When I am gliding down a paved hill at 60mph on the way back to town my transmission temp drops from the 225*f range I see while wandering off road to a relatively cool 195*f, so it doesn't seem like the thermostat is preventing the cooling fluid from circulating and cooling down.

If I could keep it down near 200-210 at worst case, I'd like to do so.
The internal thermostat probably opens at 180-185 to warm up the fluid quickly. With my cooler the temp never exceeds 200. Before the cooler summer temps towing would hit 230.
 

barongan

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Following!this seems like a very interesting thread
Jeep Wrangler JL Auto Transmission Coolers {filename}
 

Indio

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I spoke to a Jeep Engineer, they are not concerned. I put a stacked trans cooler on my jl. it made no difference, the trans, has a thermostat internal, so no matter what we do the thermostat will control. FCA makes this trans in the USA under license from ZF in Germany.
FCA thermostat may be there to make sure the trans fluid remains above the minimum operating temperature. And the aux trans cooler would be there for situations where the temps rose too high for the existing cooler to handle. That is why I had a trans cooler on my Jeep, to deal with some off-road situations that were overpowering the ability to adequately cool.
 
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heamick

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FCA thermostat may be there to make sure the trans fluid remains above the minimum operating temperature. And the aux trans cooler would be there for situations where the temps rose too high for the existing cooler to handle. That is why I had a trans cooler on my Jeep, to deal with some off-road situations that were overpowering the ability to adequately cool.
 
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heamick

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I just began my new 60 day driving trip, going up and down roads at 72 mph. after a while i noticed that the engine coolant might go to 220-230 F, the transmission stayed at 203F. So it appears the aux, trans cooler I had installed is doing its job,
 

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APEX engineering has a cooler for the steering system. perhaps it can be re-purposed for transmission.
 

Yellow Cake Kid

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I would like to pursue the idea of adding a transmission cooler. Are there any installation guides specific to a JLU Rubicon.
 

m3reno

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My dodge ram came with a cooler and I upgraded to the heavy duty cooler which was much larger and was a direct oem fit from factory. My trans lasted 250,000 before needing replacement which was covered under the lifetime warranty. Trans temps should be between 175 and 200. Anything above that reduces the overall life expectancy of your transmission.
 

Doomgaze

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I just began my new 60 day driving trip, going up and down roads at 72 mph. after a while i noticed that the engine coolant might go to 220-230 F, the transmission stayed at 203F. So it appears the aux, trans cooler I had installed is doing its job,
How were you able to speak to a Jeep engineer? My trans is hitting 230 on flat roads, and after stopping and letting the fan run for 30 minutes the temp will only go down to 220 or so. I've scanned the coolant lines and they're both hot, and get colder as the near the trans cooler, and the trans cooler is ambient air temp. I'm sure I have a clog, low fluid, or the trans heater bypass/thermostat is broken or stuck. I can't get the dealer to look into any of this, they just say the temp is fine cuz i'm not getting any codes thrown.
 

Dotan swisa

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How were you able to speak to a Jeep engineer? My trans is hitting 230 on flat roads, and after stopping and letting the fan run for 30 minutes the temp will only go down to 220 or so. I've scanned the coolant lines and they're both hot, and get colder as the near the trans cooler, and the trans cooler is ambient air temp. I'm sure I have a clog, low fluid, or the trans heater bypass/thermostat is broken or stuck. I can't get the dealer to look into any of this, they just say the temp is fine cuz i'm not getting any codes thrown.

Hi,

I have the same issue with my transmission. Get to 230 on road and higher off road.. dealer won't do nothing without a code.
I'm almost positive the issue is with the bypass heater valve. I'm thinking to take it completely. I also install mishimoto cooler in the front didn't do any different
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