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8-Speed Transmission Coolers

J

jassim

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Hey guys,

Was wondering the other day if we could add a external transmission cooler for the newer 8-speeds and how easy of a job it is.
Always done that to other transmissions (4l60e and 6l80s that I owned before), However, climate isn't that pleasing here, 94 °C (201 °F) without any load / towing.
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I know that this is under normal operating temperatures, if it helps abit why not.

Thanks!
 
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The factory 8HP75 oil cooler is fantastic. It runs 168-172 F when towing 8k
 
My transmission doesn't budge in temperature even when towing. It's locked in at 84 celsius (183F)

Sent from my SM-G781W using Tapatalk
 
99% of what I use my 2021 Laramie for is towing a 7k lb travel trailer. I've towed in heat above 100f several times this summer. I keep an eye on temp readouts. The trans temp readout is always well below 200f, but on hottest days at high speeds it will creep up above 190f. Once I slow down the temp falls.
 
Hala Jassim. :)

As everyone said, you do not need an external transmission cooler for the ZF, and I know what you mean with GM trucks transmission heating up here.
Tstat 160 is also recommended with fans kicking in @ 192F via diablo.
 
I guess I got a bad transmission then. I've been running at 242 degrees unloaded. I called the dealer and they can't look at it for 3 more weeks.
 
DarkKn1ght said:
I guess I got a bad transmission then. I've been running at 242 degrees unloaded. I called the dealer and they can't look at it for 3 more weeks.
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Wow, anything above 210F-220F is already considered high for this and most automatics. You definitely need to have that checked out, probably a replacement is in your future, though maybe it's just a sensor issue if it seems to be running fine at 242F?
 
On the other ram forum there is a member who makes replacement doodads that screw into the transmisison and permanently enable the cooler loop. I'm saying that poorly, but it's just a tiny brass piece that you replace and the transmission then always goes through the cooling loop so it's always running as cool as it can. They have experienced really good results with it, it's like $30 or something like that. Temps while towing drop significantly.
 
silver billet said:
On the other ram forum there is a member who makes replacement doodads that screw into the transmisison and permanently enable the cooler loop. I'm saying that poorly, but it's just a tiny brass piece that you replace and the transmission then always goes through the cooling loop so it's always running as cool as it can. They have experienced really good results with it, it's like $30 or something like that. Temps while towing drop significantly.
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The bad thing about that, is if you do have trans problems, if they see that on the truck, it's possible to void your warranty. Even though it may actually be better for the trans, you have modified the factory system.
 
6of36 said:
The bad thing about that, is if you do have trans problems, if they see that on the truck, it's possible to void your warranty. Even though it may actually be better for the trans, you have modified the factory system.
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You can just remove it again, it's just a little fitting. I'm not one that tries to weasel out of paying for my own mistakes, but something like this can only prolong the life of the transmission. Completely different than (say) throwing a turbo on it and then playing dumb when you blow something.
 
silver billet said:
You can just remove it again, it's just a little fitting. I'm not one that tries to weasel out of paying for my own mistakes, but something like this can only prolong the life of the transmission. Completely different than (say) throwing a turbo on it and then playing dumb when you blow something.
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I agree, I'm just stating that possibility.
 
silver billet said:
You can just remove it again, it's just a little fitting. I'm not one that tries to weasel out of paying for my own mistakes, but something like this can only prolong the life of the transmission. Completely different than (say) throwing a turbo on it and then playing dumb when you blow something.
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It is a bypass made for the transmission heater. If you are getting temps to 242F then your T-Stat in your transmission heater is broken. I know, I had the same thing with my '15. Good luck getting that fixed under warranty....they wouldn't do squat for mine. I had my transmission replaced under warranty at 56K miles. But they re-used the heater. 9K later, my trans was heating to 230F after driving it for only 20 miles. Took it into Ram dealers 3 times....3 times they said "No problem found...operating as designed." So I bought the bypass from Caulk04, put the heater t-stat and put in the bypass...now it runs at 145 -165F in beltway traffic. Ram will NOT look inside the heater...the T-Stat is NOT a serviceable part per Ram. They best you will get is a new heater. ZF8's are set to run at 180F for EPA reasons, but if the T-stat goes bad....it never sends oil to the radiator for cooling. I don't know if Caulk04 is still making the part.
 
jjjefferson said:
It is a bypass made for the transmission heater. If you are getting temps to 242F then your T-Stat in your transmission heater is broken. I know, I had the same thing with my '15. Good luck getting that fixed under warranty....they wouldn't do squat for mine. I had my transmission replaced under warranty at 56K miles. But they re-used the heater. 9K later, my trans was heating to 230F after driving it for only 20 miles. Took it into Ram dealers 3 times....3 times they said "No problem found...operating as designed." So I bought the bypass from Caulk04, put the heater t-stat and put in the bypass...now it runs at 145 -165F in beltway traffic. Ram will NOT look inside the heater...the T-Stat is NOT a serviceable part per Ram. They best you will get is a new heater. ZF8's are set to run at 180F for EPA reasons, but if the T-stat goes bad....it never sends oil to the radiator for cooling. I don't know if Caulk04 is still making the part.
Click to expand...

He is as of a few weeks ago, haven't heard that he stopped only that he might have to sometime soon.
 
The dealer installed another new transmission. I'm on my 3rd transmission...and 2nd engine. They replaced the transmission heating and cooling system too. We'll see if it's fixed or not. I've been a big Mopar fan my whole life but this truck might end that.
 
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