Is there a difference whether the trans cooler is installed bypassing on the way to the radiator or the radiator return line?The trans cooler that was recently installed looks to be bypassing the top line on the radiator. Is that the input or return? (2009 Tahoe)If so, what is the impact.Thanks

The aftermarket cooler should be installed down stream from the factory cooler. Or, you can replace the original cooler with a larger one. The fluid should travel through the radiator first as it will warm the fluid for better trans performance when cold.

I believe you're backwards there 74vette. Preferred way is to go through the auxiliary cooler first and then through the vehicle radiator. Thus if the auxiliary cooler supercools the fluid, the radiator will warm it up some. The engine thermostat makes sure the coolant coming out of the engine is 195* so after the radiator cools it down some the temperature at the trans cooler element is almost the perfect temp for the transmission.

DougE wrote:I believe you're backwards there 74vette. Preferred way is to go through the auxiliary cooler first and then through the vehicle radiator. Thus if the auxiliary cooler supercools the fluid, the radiator will warm it up some. The engine thermostat makes sure the coolant coming out of the engine is 195* so after the radiator cools it down some the temperature at the trans cooler element is almost the perfect temp for the transmission.Say What!!!!! You want your tranny fluid to run as cool as possible. Tranny, Rad, extra cooler, back to the tranny. If you start with 180 degree transmission fluid in the pan you will destroy it on a good along pull. I monitor tranny fluid in two places. In the pan and at the output line. Temp in the pan barely moves the needle most of the time. But will get to around 170 in really hot SW weather on a good pull. Get it around 235 in the pan and you are in trouble. The output line reacts quickly to stop and go traffic or mountain pass pulls. Heat destroys tranny fluid, and destroyed tranny fluid destroys trannies!!! I run Amsoil tranny fluid.Chris

It goes:Tranny, radiator, cooler (next cooler) and back to tranny.Here is why.As far as super cooling tranny that is not an issue. Tranny's have a temp sensor and they won't lock up the converter until they are up to temp.Guess what I have to replace this weekend on my old 93 pickup? Yep, tranny temp sensor. :R It went out a few weeks ago. :R Oh joy I love taking a bath in ATF. I'm Soooooooo looking forward to doing this. :R

Check out this link from Hayden coolers.Trans cooler questions

Aftermarket Trans Cooler | Good Sam Community

12 Replies

DougE
Explorer
Oct 25, 2013
I believe you're backwards there 74vette. Preferred way is to go through the auxiliary cooler first and then through the vehicle radiator. Thus if the auxiliary cooler supercools the fluid, the radiator will warm it up some. The engine thermostat makes sure the coolant coming out of the engine is 195* so after the radiator cools it down some the temperature at the trans cooler element is almost the perfect temp for the transmission.
74vette
Explorer
Oct 25, 2013
The aftermarket cooler should be installed down stream from the factory cooler. Or, you can replace the original cooler with a larger one. The fluid should travel through the radiator first as it will warm the fluid for better trans performance when cold.

Forum Discussion

Aftermarket Trans Cooler

12 Replies

About Travel Trailer Group

Related Content

Trans coolers

Trans cooler

Towing without trans cooler?

Silverado trans cooler upgrade?

Trans cooler installation.