Tip Experts: Coolant Radiator Heat Exchange for Transmission Fluid - To do or not?

[ColinGruenfeld]

Hello all! I am in the final stages of assembling my stage III Tiptronic S4 and am currently debating a transmission cooling configuration.

The vehicle has a build transmission that WAS configured to pass fluid as follows:
Transmission
Aftermarket cooler (shown in photos)
Engine coolant radiator end-tank for heat exchange
OEM cooler
Transmission.


OLD trans cooler on bottom left

Top of radiator end-tank for transmission fluid to run through for heat exchange.

The configuration is setup with barbed fittings with lots of leak potential/pressure losses through long runs. I want to make a more simple and efficient setup that runs strictly on AN fittings, preferably with one large fluid cooler only. Since the end-tanks do not run AN, I would likely have to use barbed fittings if I wanted to continue with the OEM coolant heat exchange concept.

My question is the following: Is it necessary to route the transmission fluid back into the radiator end-tanks for heat exchange? The car is equipped with 3" unwrapped downpipes, therefor I would imagine they might aid in cold-weather warm-ups, as was the original purpose of the coolant heat exchange, if I understand correctly. There was just too little space to squeeze wrapped downpipes in the engine bay, and not enough in the budget to ceramic coat them.

Thanks again for all of your time!

[dannyn424]

I bought a B&M transmission cooler but never got i hooked up? should i do it? Im running amsoil fluid currently

[MacDaddy]

From what I understand the heat exchanger in the rad helps the transmission fluid get up to temp, bypass it and check fluid temp with vag com.

[ColinGruenfeld]

From what I understand the heat exchanger in the rad helps the transmission fluid get up to temp, bypass it and check fluid temp with vag com.

Thank you. I think this is likely the route that I will go. As I had mentioned, I would imagine that my unwrapped downpipes will help raise transmission temperatures from a cold start. Hopefully they don't cook the transmission.

Ideal transmission temperatures to look for during daily driven operation?