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Whats the best way?? (trans cooler)

wowitsfast

wowitsfast

New member
For Christmas my wife got me a transgo and a trans cooler (shes good like that). My question is on the cooler, ive read two ways of doing it. One trans to cooler to trans and the other is trans to cooler to rad to trans.

I understand running it through the radiator to keep the fluid @ operating temp but if the radiator isnt doing a good job of cooling the fluid is it a good idea to use the radiator?

Is it a big deal to have the fluid below operating temp and just bypass the radiator all together?

thanks in advance for your feedback
 
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Re: Whats the best way??

It's pretty rare to ever see the trans temp up around the coolant anyway unless you are driving up mountains or it's a million degrees outside in a 97-03 car.

I never ran a cooler but with the stock rad style cooler, temps always stayed around 150-180 in the summer and thats perfect for trans temp. But even in the winter temps were always lower, maybe 100-140 unless I was running it hard.

If you wish to never deal with the radiator cooler splitting and have coolant dumped into the transmission, run the cooler seperate. Temps will be lower all around for sure but might get too cool in the winter time. Sticking some cardboard around in the winter will help keep the temps up.

My silverado has a trans cooler directly infront of the radiator and with the winters here it's hard to even get the fluid temp above 120-130 and I sometimes feel it's too cold. I will someday put some cardboard behind the grille to stop airflow over it to help raise the temps.
 
Re: Whats the best way??

My trans has been as high as 235 in the hills around portland hence the cooler. If strait cooler with cardboard in the winter is good then ill hit that route. thanks fellas
 
I haven't had the car on the road long enough to see the difference because I've been fighting a vacuum leak. My transmission has hit 235 once or twice as well.
 


I hit high 220's and probably even in the 230's when I was in the mountains before my cooler. Since the cooler install (ran in series) I don't think I have hit 200. Highest is usually around 190, but average is around 170.
 
I would run the aux cooler before the radiator. The cooler in the radiator was designed to try to keep your fluid in the correct temp range. If your trans is running extreme temps, the aux cooler will drop them some, then the cooler in the radiator will reduce them further but no below the desired operating range. Setting it up this way will also warm your trans fluid if its too cool, before returning it to the trans.

Running it after the radiator may keep the fluid too cool and/or take the fluid much longer to get to the operating range. Not using the radiator may result too much or not enough cooling. The cooler in the radiator is the last stop for fluid to be cooled or warmed before returning to the trans.
 
Cut the radiator out of the equation altogether. You can even use the stock hoses if you cut off the crimped ends, they have barbs under those fittings that will go into the new lines, it makes for a pretty easy install.
 
All good stuff. What are the cons of running the trans at lower then normal operating temp? Will cause it not function properly ie up/down shifts
 
I don't think you have much to worry about.....heat is what kills them, and like was said earlier, if it's not warm enough then cardboard works.
 


You can always run standalone first, and see how you like it, using the method that Reptile mentioned. If afterward, you have concerns about temps, you can use the cardboard as mentioned OR you can reconnect one of the factory trans lines, then run your cooler in and out through the ends of the other line. That will restore your radiator cooling in addition to your cooler.
 
2nasti said:
I would run the aux cooler before the radiator. The cooler in the radiator was designed to try to keep your fluid in the correct temp range. If your trans is running extreme temps, the aux cooler will drop them some, then the cooler in the radiator will reduce them further but no below the desired operating range. Setting it up this way will also warm your trans fluid if its too cool, before returning it to the trans.

Running it after the radiator may keep the fluid too cool and/or take the fluid much longer to get to the operating range. Not using the radiator may result too much or not enough cooling. The cooler in the radiator is the last stop for fluid to be cooled or warmed before returning to the trans.
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I have never heard of someone running the cooler before the radiator. Your car is set up stock to utilize the radiator to warm your trans fluid in the winter and cool your trans fluid in the summer. If you want additional cooling, you have to do that after the radiator has had it's impact on the fluid temperature.

My understanding of the stock system is that the trans fluid temp will chase your coolant temp. If you set up 2nasti's way, and your transgo ever gets the fluid cooler than the radiator could, the trans fluid temp will RISE once it gets to the radiator. My opinion is let the radiator do it's work and then let the auxiliary cooler do more after the majority of the cooling is done.

If you set it up the way 2nasti is suggesting, my opinion is you are wasting the cooling efforts of your auxiliary cooler.
 
There is no one answer.

In the summer, I see temps of 200* within 40-60 minutes of driving; city of highway. In the winter, I am currently seeing temps of 180-190 after the same amount of driving.

Still debating on stand alone or not. Ideally I need stand alone in the summer, and thru the rad in the winter. Would be nice to keep ATF out of the radiator for when the rad goes.

Hoping to install this in the spring, but have been saying this for the past 3 years now. :)
 
I agree there is no one correct way, those are just my opinions based on what I've observed here. Stand alone is likely best for all out summer cooling.
 


stocker said:
I have never heard of someone running the cooler before the radiator. Your car is set up stock to utilize the radiator to warm your trans fluid in the winter and cool your trans fluid in the summer. If you want additional cooling, you have to do that after the radiator has had it's impact on the fluid temperature.

My understanding of the stock system is that the trans fluid temp will chase your coolant temp. If you set up 2nasti's way, and your transgo ever gets the fluid cooler than the radiator could, the trans fluid temp will RISE once it gets to the radiator. My opinion is let the radiator do it's work and then let the auxiliary cooler do more after the majority of the cooling is done.

If you set it up the way 2nasti is suggesting, my opinion is you are wasting the cooling efforts of your auxiliary cooler.
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I have seen it run every which way. Here is why I suggest the way I did, yes the other works too.

Like you said, the trans fluid will try to equal the coolant of the radiator, which should be close to ideal trans fluid temps. If run the way I suggested, even if the aux cooler before the rad makes the fluid too cool (say 140*?) the radiator should bring it back up before sending it to the trans. If the trans fluid was so hot the aux cooler before rad could not get it low enough, say 225*?, the radiator should bring it down further before sending it back to the trans. Seems like either way the fluid should be under control and not too cold. The trans fluid will try to equal the coolant in the radiator, which is less than the reading on your dash. I don't see a downside unless there is an extreme trans overheating issue, and I think the aux after the radiator would then show its superior cooling ability.

The only downside I see with the aux after the radiator is if the fluid leaving the radiator is ideal, it is about to be cooled further, possibly below ideal. Like I said, I have seen them both ways and neither had issues. I just like the idea of the radiator having the final say, as it will either cool down fluid further if its hotter than the coolant in the radiator, or raise the cold atf closer the radiator temp but never higher. The aux cooler can only reduce the temp further.

Try the aux cooler after the radiator, if you don't like the temp range, try it the before the radiator. You can recheck it in the summer too.
 
Great conversation. I've been casually researching this topic for the past few years. I found good info on the install and such, but nothing on "why" people did the install the way they did. Good to see some "why" happening here.

I don't get why these trannys get so hot. In my old Bronco, I used to beat on it for 10-14 hours at a time (WAY more abuse than the GP has ever seen), and I never had heat issues at all. I am starting to believe that the radiator in these cars is insufficient.
 
2nasti said:
I have seen it run every which way. Here is why I suggest the way I did, yes the other works too.

Like you said, the trans fluid will try to equal the coolant of the radiator, which should be close to ideal trans fluid temps. If run the way I suggested, even if the aux cooler before the rad makes the fluid too cool (say 140*?) the radiator should bring it back up before sending it to the trans. If the trans fluid was so hot the aux cooler before rad could not get it low enough, say 225*?, the radiator should bring it down further before sending it back to the trans. Seems like either way the fluid should be under control and not too cold. The trans fluid will try to equal the coolant in the radiator, which is less than the reading on your dash. I don't see a downside unless there is an extreme trans overheating issue, and I think the aux after the radiator would then show its superior cooling ability.

The only downside I see with the aux after the radiator is if the fluid leaving the radiator is ideal, it is about to be cooled further, possibly below ideal. Like I said, I have seen them both ways and neither had issues. I just like the idea of the radiator having the final say, as it will either cool down fluid further if its hotter than the coolant in the radiator, or raise the cold atf closer the radiator temp but never higher. The aux cooler can only reduce the temp further.

Try the aux cooler after the radiator, if you don't like the temp range, try it the before the radiator. You can recheck it in the summer too.
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Great points and discussion! After reading this, I think either way could work well.
 
Thanks a ton guys. Ive learned a lot reading this. Im going to run it stand alone like reptile and FFDP suggested. In said that low temps isnt a big deal then to me its a good option. Average winter temps in my parts is in the 40s and if its icy out im not driving the gp anyways.

Like stocker 2nasti and Impala131 said I can always reroute the lines to suit my needs.

Thanks again for the great info
 
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