Hey, I have an auto & are currently only cooling the trans via an aftermarket PWR trans cooler.
This is what I did & the results that I got in my particular circumstance.
Firstly my car is a JDM 370GT (G37) & has the 5AT so the results may be different to the 7AT.
I have also fitted the Transgo shift kit.
Where I live (on the east coast of Australia) Temperatures are Moderate to Hot (no snow or even frost).
I have an auto rad in the car but have disconnected the stock trans cooler completely.
I did this as a bit of an experiment as a part of building my own TT system.
Reason behind this was to see how trans temps reacted.
I wanted to see if I could use the CSF triple pass (manual only) Unit to combat the extra heat generated by the TT system & still keep trans temps under control.
I fitted a transmission temp sensor to the trans pan early on, before even doing the shift kit, so as to monitor changes in trans temp from mods.
I also fitted coolant, engine oil & differential oil temp sensors, etc,etc.
So far its all good, currently it is still NA though.
For me it is actually an improvement over stock, the only negative is a slightly slower warm up time (almost negligible) & a way faster cool down once it gets hot.
Again you must remember, it never gets real cold here & the result may be quite different in a colder climate.
Another big plus that became evident though was the effect that this had on the water cooling system.
Under sustained hard driving I had previously had trouble with excessive coolant temps.
Reducing the thermal load on the coolant (it now doesn't have to cope with cooling the trans) has made a substantial difference. Coolant temps are now totally under control & that is still with the stock auto radiator in there.
I have since purchased said CSF Manual triple pass Radiator to fit as a backup if needed when the turbos go on.
Mind you, as previously mentioned it is still NA & this may all change when the intercooler is mounted up front.
I did the same thing with the oil system & removed the stock oil cooler/heater (JDM models have had it since late 2007) & replaced it with a thermo plate, setrab 25row cooler & oil pan spacer.
So currently I have quite a bit of headroom.
