Transmission cooler

Gordo

Original poster
Member
Mar 26, 2012
81
I want to ad a tranny cooler to my 02 Avalanche as I only have the radiator side tank version now and want to pull a trailer this summer. Should I leave that plumbing connected as I live in Canada where we can see some cold winter weather? If so should the rad come before or after the new cooler?
Any suggestions on the actual cooler? I see quite a few on line!

Thanks
 

Conner299

Member
Jan 16, 2013
279
As far as I know, the trans cooler comes after the radiator cooler. You dont want to cool the trans fluid, only to warm it back up by routing it back through the radiator cooler.
 

Gordo

Original poster
Member
Mar 26, 2012
81
Makes sense! Do you know the direction of flow? Is the hot oil going into the bottom or top of the radiator??
 

Conner299

Member
Jan 16, 2013
279
This, I do not know. Especially since I don't have an Avalanche, and don't know quite what you're working with.
 

jimmyjam

Member
Nov 18, 2011
1,634
Gordo said:
Makes sense! Do you know the direction of flow? Is the hot oil going into the bottom or top of the radiator??

While I am not certain, generally the return should be on top. otherwise, air would be trapped in the cooler.
 
Dec 4, 2011
520
I live in the same cold climes as you and I wouldn't run a vehicle without a cooler. They are just as important in winter as summer since you would not believe how quickly a tranny can warm up when you are a stuck in snow.

Anyway I prefer the Tru-cool with the automatic bypass. When the oil is cool it bypasses the cooler and when it heats up well, it doesn't. I run mine all year around and have for years. By the way I have a 4589 model installed in the pics below.

By the way the proper hook up is: Tranny to Radiator cooler input, Radiator cooler output to Aux Cooler input, Aux Cooler output back to tranny. You just have figure out which lines are which. Don't know about you Avalanche but ou

Here is a pic of my install in the Denali

My tranny cooler hook up with pics - Page 3 - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

one of these days I will figure out how to post pics here.
 

Mark20

Member
Dec 6, 2011
1,630
Generally the external cooler comes after the radiator cooler. You can always put a piece of cardboard over the external cooler in the winter.

The recommendation I've seen is to feel the coller lines and see which is hotter and which is cooler. Just don't chop your fingers off while doing that!
 
Dec 4, 2011
520
Mark20 said:
Generally the external cooler comes after the radiator cooler. You can always put a piece of cardboard over the external cooler in the winter.

The recommendation I've seen is to feel the cooler lines and see which is hotter and which is cooler. Just don't chop your fingers off while doing that!

Agreed the cardboard will work to reduce cold air flow across the cooler. Still like the automatic feature of the Tru-Cool units. Not sure I would rely on the hotter/cooler line touch. The tranny oil will be running around 150-200 degrees not sure I can tell the difference with my hand which is the colder side. With a little help from Mr. Google you should be able to find out which line inputs warm fluid to the radiator tranny cooler and which line exits the radiator cooler. With this determined the hook up is very straight forward.

Good luck but you won't need much just a little time and TLC. :thumbsup:
 

Mark20

Member
Dec 6, 2011
1,630
I forget to mention there is a little device that you can put in line to the cooler that senses the air temperature (or maybe the fluid temperature) and bypasses the cooler or not.

I've got to search here and the OS to find the brand.

Edit:
Found it, Tru Cool Remote External Bypass http://www.transmissioncoolers.us/708-4739P6.html
 

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