deryll1,

You just can't go wrong, keeping your Cooling System in good shape. You really should give it the same (but extended) attention, as you do your Engine Oil and other Lubes. I personally would love to see Transmission Oil Temp control become a OEM/standard application on all AT Vehicles, as long as it was sophisticated enough, to really help full time.

IOW: I don't like the idea of it burdening the Engine Cooling system when cooling is required. The bypass technology is better I think.

Yes, that seems to be the way most do it, and, it's probably the less costly and most passive approach, to initially warm and then cool. HA, I just don't agree that is the best way.

 

Keep in mind the radiator does not get as hot as the engine... the engine maintains its 195 temp with the thermostat letting small amounts of cooler water in from the radiator...
I have had my display on the trans temp before on a cold day 30-40s on an 18 mile drive home in mild traffic and only saw the temp reading reach 99! as the high, while the engine was at operating temp much sooner....

 

I agree, there's a delay/differential, there's a considerable delay in what's actually happening, and what's being told by the Gauge. An additional instance is where one rarely sees the surges in temperature on the Gauge, when we have to stop suddenly, and the Coolant spikes in temp.

But, when Towing/other instances, where the workload is causing high temps in the Transmission and engine, that heat from the transmission is delivered directly into the bottom of the radiator, right where it is then fed into the engine. Usually, most Tranny Fluids are "rated" to operate optimally at 175°-200°, and I can see that getting out of hand when situations require the thermostat to be at or near full open. The stock Aux-Coolers I've seen, are really small, and generally placed where the heat they do dispel, is fed right into the air flow to the A/C Condenser and/or Radiator.

I readily admit, that system works well enough most times, but I'm not beyond splitting hairs about this, and any number of other things.

What I'd like to see is a Thematic Valve, shifting the TFluid flow completely away from the Radiator starting at 175°, and fully open/transferred by 190° or so. Then, a reasonably sized Aux-Cooler placed where the frontal air pressure takes it's heat down/out under and away from the Radiator. Then a kick a$$ little Electric Fan on it, set at about 200°.

That would be a system, I'd be comfortable with