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I just towed yesterday through Wyoming with my GX. Pulled my 5500 lb TT and was fighting a 10-15 mph headwind. I am running a big Hayden cooler(I think a 678?) and the hottest I saw my trans temp get was 205F and this was with my foot buried climbing a 7% grade. Vast improvement over the OEM setup.
I am honestly not sure you can get much lower than 200 or 205 regardless of how much cooler your throw at it simply because of the thermostat that controls the cooling loop. My F150 is much the same way. Whether I am towing or not, my transmission runs between 200-205 all the time. I upgraded my stock air cooler to one from a V10 excursion that was literally 3x the size and it maybe improved my temps a couple of degrees because the thermostat simply wont let it get any cooler.
10760967[/url]]I'll need to find post or data but I think that valve doesn't open until over 200°F or greater.
I'll have to go back through my thread and see if I ever posted any graphs of cooler temps with and without pinned thermostatic switch after cooler was installed.
OBD AT temp monitoring is an easy way to tell what difference it makes.
i would agree with this. Even with my pretty large Hayden cooler it still never really goes below 200F. It basically swings between 200 and 210 or 212 towing my TT.
my F150 is the same way. Once the transmission gets to 200F it pretty much never gets any lower. I can coast down Parley’s Canyon, which is basically 10 minutes of never touching the gas, and it still stays at 200.
The Hayden Install looks relatively easy and inexpensive compared to the OEM, any comments on why one over the other? Interestingly I just called an independent Toyota specialist and they said they would not install an aftermarket cooler, only OEM.
The Hayden Install looks relatively easy and inexpensive compared to the OEM, any comments on why one over the other? Interestingly I just called an independent Toyota specialist and they said they would not install an aftermarket cooler, only OEM. Then I called my local "Import" Specialist and they told me they have installed many aftermarket coolers with no problems. The aftermarket is a few hundred Dollars as opposed to $$$$ for the OEM.
The Hayden Install looks relatively easy and inexpensive compared to the OEM, any comments on why one over the other? Interestingly I just called an independent Toyota specialist and they said they would not install an aftermarket cooler, only OEM. Then I called my local "Import" Specialist and they told me they have installed many aftermarket coolers with no problems. The aftermarket is a few hundred Dollars as opposed to $$$$ for the OEM.
For any radiating cooler ... engine coolant or automatic transmission ... it's all about the specs ... tubing diameter, number of passes, cooling fin density and the materials used in both to provide maximum heat transfer. Not all are created equal. If you do not tow ... then aftermarket may be acceptable based on the ambient driving temperatures. If you are under the warranty period, aftermarket may void your drive train coverage.
Hard to find specs on an OEM add on, the built-in cooler is 13,000 - 14,000 BTU's most of the after markets claim 20,000 - 40,000BTU's
That might be accurate. The stock cooler is pretty small. Most aftermarket ones seem to have more frontal surface area and thickness. There is a lot of room up front to mount a bigger heat exchanger than the stock cooler, but the way the thermostat works it might be a waste.
For any radiating cooler ... engine coolant or automatic transmission ... it's all about the specs ... tubing diameter, number of passes, cooling fin density and the materials used in both to provide maximum heat transfer. Not all are created equal. If you do not tow ... then aftermarket may be acceptable based on the ambient driving temperatures. If you are under the warranty period, aftermarket may void your drive train coverage.
"If you do not tow ..." - is a dedicated transmission cooler even needed if you don't tow?
Just my opinion but it might depend on elevation gain you drive, primarily city driving and/or heavy loads as well? Can you keep your AT in lockup most times when cruising as this keeps AT heat down? I think you have to self-monitor temps and then ask yourself if you are comfortable with that. It will really come down to your gut feeling.
I figure if nothing else you are improving the odds that you won't have any transmission issues with an external cooler and AT fluid changes.
Looking at new criteria in '22 for transmission fluid replacement schedule at 60k miles they even added extended idling.... 10-21 always had the other conditions along with "heavy vehicle loading".
We are starting to see some occasional higher mileage 460s with AT problems.. not widespread but you can find them. Is this because fluid was never changed? Not sure we will know for sure on that. A cooler should help extend AT fluid life though.
The AT in 460 isn't much different than A750 used in the GX 470. Aside from one less gear most GX 470's had an external AT cooler. Just a few thoughts.
09-30-20, 04:07 PM
