So I was walking out of my local wrecking yard, when I saw a truck with a nice aftermarket trans cooler just sitting there (front grill removed, easy access).. So I pulled it off to add to my kia.. Then I thought maybe it's too large ?? Could that cause issues with the trans as well ?? Also,on the truck it was mounted in front of the AC condenser. While this is an easy place to put it, would it not effect the AC performance ??ThanksJosh

Josh, on my 07 GMC Sierra the trans cooler is mounted in front of the A/C cooler which is in front of the radiator. I think most vehicles are that way. As to the oversize, I have an oversize one on my truck. Do i need it in the cooler weather, NO. Do I need it in the summer when towing up long upgrade and backing down on long downgrades, Yes. Maybe you need one maybe you don't. You need to research it more. How is your TV doing now?

It's possible but doubtful. The only time it would be too big is iff you were unloaded and the trans temp never got up to 140 degrees. In that case the fluid wouldn't burn off moisture and may get contaminated.

Many newer vehicles won't let the torque converter go into lockup until a minimum temperature is reached. Probably not an issue in SC.

I have always thought it should be installed before the radiator so that if the fluid is cooled too much it will be warmed to the proper temperature before going back to the transmission. Others disagree.What do you all think?

wgriswold, That was always my thought and at one time it may have been accepted practice. Nowadays it's vehicle radiator first and auxiliary cooler second. Auto manufacturers seem to be more concerned about overheating than running too cool. I think, and maybe someone can confirm, that modern automatic transmissions now have temperature sensing that recirculates the fluid until it gets warm before allowing it to go to the cooler.

Can you have too large of a trans cooler ?? | Good Sam Community

kayco53
Explorer
Jan 07, 2015
My cooler came with a thermostatic bypass for cold weather.
christopherglen
Explorer
Jan 06, 2015
I put the largest cooler I could fit behind the grill of my duramax, the Allison has no problems shifting summer or winter, and the summer temps are 15-20 degrees cooler, when it heats up (extended climbs) it cools faster on top. I don't run where it is stupid cold, but 0f empty it has no problems.
tatest
Explorer II
Jan 06, 2015
Not if you install it properly. If you put the transmission fluid cooler in series with the OEM intercooler in the radiator, with fluid going through the intercooler last, then over-cooled transmission fluid should be warmed back to operating temperature before going back to the transmission.
TNRIVERSIDE
Explorer
Jan 06, 2015
It would seem to me that if you have a factory trans cooler with a thermostat that controls the flow until the proper temperature is reached then you could run a larger unit safely. If your TT did not have a towing package and you are adding a transmission cooler you could create a undeserable condition. You really need to know you vehical.
BurbMan
Explorer II
Jan 05, 2015
Turtle n Peeps wrote:
Yes, you can cool the tranny fluid too much. If you don't have a thermostat it can keep the ATF too cold and not burn off the water. That is why OEM putters don't lock the converter up for several miles. They want the ATF to come up to temp.

Good answer here. I would recommend installing a trans temp gauge so you can see what temps you are running at both empty and when towing, then you can make an assessment about how large of an external cooler you want to add or if you even need one.

Theoretically, you can't have a cooler that's too large when towing, but as Peeps pointed out, you don't what the transmission to stay tool cool when not towing, which is most of the time for most of us.
Community Alumni
Jan 05, 2015
Years ago I swapped my trans cooler on my Ram 1500 Hemi with one from a 3500 Hemi. I read that they were a direct swap so figured what the heck. I knew where to get one for cheap so I swapped it out. It's about 3 times the size of the original one I had. I haven't had a problem running the larger cooler and I'm running empty most times. But then again I'm in Texas. It gets pretty hot down here and we don't have much of a winter. Anything less than 65° and people start saying that it's "freezing" outside lol.
Fast0ne
Explorer
Jan 05, 2015
I know on my chevy colorado it will not let the tranny go into 4th gear until it is warm enough which is 70*f.

I installed a B&M cooler and in the winter takes a bit to get up to temp but once there all is good. But I live in vancouver bc so we don't have to many freezing days.

But B&m does make a tranny cooler with a bypass for colder temps.
DougE
Explorer
Jan 04, 2015
Turtle n Peeps wrote:
DougE wrote:
Turtle n Peeps- but then how do you keep the transmission fluid circulating? (The engine coolant continues to circulate through the heater when its thermostat is shut.)

This is how.

Or this.

Thanks, just didn't want anyone to forget about maintaining circulation.
MitchF150
Explorer III
Jan 03, 2015
Do you know what your trans temps are now? (towing and not towing).

Until you know that, it's really just a guess as to what you need... ;)

I put an aftermarket trans temp gauge on my 97 F150 to find out how the OEM aux trans cooler was doing..

Determined that it was just fine and I didn't need any additional cooling. :)

Even it had a thermostat controlled fluid flow, but it's internal, so the fluid circulated inside the trans until it opened and went to the coolers.

Good luck!

Mitch
Turtle_n_Peeps
Explorer
Jan 03, 2015
DougE wrote:
Turtle n Peeps- but then how do you keep the transmission fluid circulating? (The engine coolant continues to circulate through the heater when its thermostat is shut.)

This is how.

Or this.