Transmission Thermal Bypass

[Fozzy]

My Expy tows a lot. Last trip to Mead was 100*-115* and on steep long grades both the motor and Trans got warm. No warning signs or limp mode but hot. Kept the pedal down to see what happens. Nothing, it recovered as soon as the grade lessened. The 10R80 and new EcoBoost are known to run a little hotter than previous Gens. I ran across this thermal bypass eliminator. Any of you run it? It’s cheap but not sure if it’s worth my time as I have temp swings from below freezing to 100*+ in Utah. It basically stops the Trans from heating up before it opens to the cooler. And does not restrict the flow through the smaller orifice of the stock bypass. Any thoughts?


https://revmaxconverters.com/product/10r80-transmission-cooler-thermostatic-bypass-upgrade/


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[99WhiteC5Coupe]

My belief is that Ford engineers included the thermal bypass for a reason.

If you’re towing in very hot weather, it will open very quickly.

If you’re towing in sub-freezing weather, it will open as designed.

The bypass is designed to have the transmission fluid heat up to the desired temperature quicker in cold weather.

Elimination of the feature may void your power train warranty - if that is a concern.

 

[Fozzy]

Elimination of the feature may void your power train warranty - if that is a concern.

That is a good point on the warranty. From what I have read Ford uses this to help increase fuel mileage on cold starts. But the new design can overheat the motor or transmission. Once you have heat soaked both your done.


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[Greg Parker]

That is a good point on the warranty. From what I have read Ford uses this to help increase fuel mileage on cold starts. But the new design can overheat the motor or transmission. Once you have heat soaked both your done.


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The other thing I noticed is that while that link's blurb speaks of "all 10R80" transmissions ...there is a very confusing line at the end of the Product Description that states...

"This product ONLY fits 2017-2021 Ford Raptors."

...but then in the "Additional information" section says it works with F150s & Mustangs. So...I'd definitely call that vendor before ordering to ensure that it'll bolt-up to the Expy platform (it should...but I'd wanna verify).

Back on the warranty thing. I am going to consider researching this a little more with my dealer. Here in AZ, my rigs only see sub-40F ...well, almost never. My Expy could see lows of 20-30F for a few days during hunting season, but that's about it. It sure would be nice to have an option for a cooler thermostat for those of us that are constantly driving and towing in triple-digit temps.

 

[AKentPhoto]

I'd personally rather enlarge cooling capacity than remove factory parts.... While under warranty...

 

[99WhiteC5Coupe]

The other thing I noticed is that while that link's blurb speaks of "all 10R80" transmissions ...there is a very confusing line at the end of the Product Description that states...

"This product ONLY fits 2017-2021 Ford Raptors."

...but then in the "Additional information" section says it works with F150s & Mustangs. So...I'd definitely call that vendor before ordering to ensure that it'll bolt-up to the Expy platform (it should...but I'd wanna verify).

Back on the warranty thing. I am going to consider researching this a little more with my dealer. Here in AZ, my rigs only see sub-40F ...well, almost never. My Expy could see lows of 20-30F for a few days during hunting season, but that's about it. It sure would be nice to have an option for a cooler thermostat for those of us that are constantly driving and towing in triple-digit temps.

A cooler (than stock) engine thermostat does not help an engine run cooler in hot ambient temperatures - it only opens slightly faster than a stock thermostat.

Once the engine thermostat opens as the engine reaches operating temperature, it remains open - as the engine runs hotter that the opening temperature of the thermostat (especially with triple-digit ambient air temperatures and towing).

The engine thermostat is designed to help the engine warm up quicker, which aids in emissions control, oil lubrication and helps to provide heat quicker for cold ambient temperatures.

 

[Greg Parker]

A cooler (than stock) engine thermostat does not help an engine run cooler in hot ambient temperatures - it only opens slightly faster than a stock thermostat.

Once the engine thermostat opens as the engine reaches operating temperature, it remains open - as the engine runs hotter that the opening temperature of the thermostat (especially with triple-digit ambient air temperatures and towing).

The engine thermostat is designed to help the engine warm up quicker, which aids in emissions control, oil lubrication and helps to provide heat quicker for cold ambient temperatures.

Yeah...I do understand the principles having a thermostatic block.....for the engine coolant; however, that is a much less viscous medium and takes longer to heat-up (longer than other engine temps), which can be very stressful to the materials of the engine (block/heads), if the temperature variance becomes to great.

I fail to see how this translates to fluid in a transmission (which has a very low freezing point compared to engine coolant). So, when I see these thermostatic blocks on a transmission ...and they being the first I've personally ever heard of ...it seems like there is some design-flaw in the 10R80 (that is too hard...or expensive to engineer out). Which makes this "thermostat" seem like a band-aid to a larger problem; but admittedly may be unavoidable with such an advanced tech gearbox.

In any event, I'll just be babying this bugger to death, but would love some solid way to keep the trans temps below 230F when towing (heck...in this AZ heat, I saw 219F the other day driving myself to run an errand).

 

[Fozzy]

The other thing I noticed is that while that link's blurb speaks of "all 10R80" transmissions ...there is a very confusing line at the end of the Product Description that states...

"This product ONLY fits 2017-2021 Ford Raptors."

...but then in the "Additional information" section says it works with F150s & Mustangs. So...I'd definitely call that vendor before ordering to ensure that it'll bolt-up to the Expy platform (it should...but I'd wanna verify).

Back on the warranty thing. I am going to consider researching this a little more with my dealer. Here in AZ, my rigs only see sub-40F ...well, almost never. My Expy could see lows of 20-30F for a few days during hunting season, but that's about it. It sure would be nice to have an option for a cooler thermostat for those of us that are constantly driving and towing in triple-digit temps.

Ford introduced the Gen14 F-150 in 2015. They did not get the 10R80 until 2018 The Gen2 Raptor was introduced in 2017 with the 10R80. The first truck to have it, one year earlier than the rest of the trucks. Raptor had a few years off the assembly line.


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[Fozzy]

In any event, I'll just be babying this bugger to death, but would love some solid way to keep the trans temps below 230F when towing (heck...in this AZ heat, I saw 219F the other day driving myself to run an errand).

For sure, I have had mine up to 240 Trans and engine temp. They seem to stay the same once heat soaked pulling the boat. According to the F-150 guys the water temp over temp is 250* then it goes into limp mode until it cools down. The Trans temp max temp is 255* before it reduces power. I am going to try and get ahold of them this week. Not sure where it actually goes.




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[Expedition Dave]

Where is the transmission-cooler mounted on our late model Exes? I am guessing ahead of the main radiator? Might it be easier to mount a small electric fan, or a higher capacity trans oil radiator, or open the grill/front valence a bit, etc (if it is buried)?