transmission getting hot while stop or city driving even with cooler help

[vmarcial27]

hope everyone is safe during these hard times.

so a fews months ago during the summer i upgraded my transmission oil cooler for the maxcool transmission oil cooler, which made a hugeeeeee difference. transmission tem drop from 175-180f in the city to 135-140f in city during the summer months here in new jersey. however now my transmission is running hot compare to how it was. now while the car is idling the tem will go to 180s the moment i start driving it will drop to 150-160f city driving and 120f highway when the temperture is 60 degrees outside. no oil leak or cooland leak. 08 yukon denali 170k. this started 2 weeks ago

 

[OR VietVet]

Sounds like the radiator cooling fans are not working properly. Is the trans fluid full? Trans fluid clean? Any blockage at the front area that would hinder air flow?

 

[vmarcial27]

trans fluid is clean and full i change it when i installed the cooler

 

[08grey]

My trans on my 6.2 hits 190 all the time with cooler when I idle and during nyc traffic. Fluid is clean.


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[thompsoj22]

what PNW said, It is allmost unrealistic to expect 135 degree trans temp in stop and go city unless you have the monster 700 watt cooling fans? next time you drive it when you get home let it sit in the driveway at idle and open the hood, at some point both fans should cycle from low to high and high to low, this could take 5 to 10 minutes of idling so be patient. If the fans dont cycle to high or only run on high than check your high and low relays in the underhood fuse box. they are clearly marked and easy to replace.

 

[donjetman]

190* is not ******* Dexron VI atf. 210* is not ******* it either. Call Tom Johnson at JG Lubricant Services, 877-971-7799 x2, I have. He directed and managed the testing and approval of hundreds of transmission fluid formulations for Allison Transmission and served as a key member of the GM Automatic Transmission Fluid Committee. He also acted as the Transmission Fluids Engineer for Allison Transmission.

I use JG Lubricant Services for all my used trans fluid analysis. When I have a question I pickup the phone and get answers from an expert.

https://jglubricantservices.com/home.html

https://jglubricantservices.com/docs/Technical Information Sheet.pdf