Is the transmission oil heat exchanger too weak to protect 10R80 transmission?

[duneslider]

I'm certainly no expert here but I think there are multiple things going on and not just a thermostat issue. There have been a lot of issues with thermostats not working correctly and for some reason ford has change the replacement part to a lower temp thermostat. I think the original stock thermostat opened at 203-205 the new ones appear to be 190deg. An improperly functioning thermostat obviously is a problem.

Since these are also forced induction I think there can be other issues that may be attributed to heat soak so the better you can keep the engine cool initially the less likely that is to happen. Once they get to a certain temp its hard to get them back down. Most problems seem to happen in prolonged high load and low air flow. You have a better chance at keeping this in check if the cooling starts at a lower temp.

Ford is trying every trick they can to get a little more epa efficiency out of it and so if the most efficient running temp is higher they want to try to stay there even though that may not be the best for everyone's situation. I have only experienced temps climbing when I have been at higher altitude 8000+ feet, heavy load, high ambient temps and going slow. Last time I went to this area there was no traffic and I was able to maintain 35mph (speed limit is 25mph) and I had no issues but on previous trips when I was in traffic and had to go 25mph things would get hot. Once I hit the dirt I put it in 4lo and that decreases the load on the engine and even though I am going even slower the temps quickly move back down to normal operating range. My theory is that if the engine starts cooling at a bit lower temp I might make it further up the hill before I start seeing the temps get too high.

It also doesn't help that the radiator is trying to keep the engine cool, the oil/turbos cool, and the transmission cool. It is probably undersized for needing to do ALL that work.

 

[BMW2FORD]

100% agree on the radiator. Most cars and trucks that have 300-400 horsepower and tow usually let out at least 3 gallons when you drain the radiator and they are much thicker than what’s in these trucks. People that use the Mishimoto have really good luck since it’s twice the thickness and holds a lot more coolant. We’re trying to hold off the overheat with a little bit of a cooler T stat which is the easiest thing per dollar but ideally, a bigger radiator would let the truck stay at whatever the rating was of the t stat even full blast up a hill towing.

 

[Hellwig]

Most high end cars and commercial equipment use water (engine coolant) to trans oil since not only does it cool the trans but gets the trans warmed up quicker and also keeps the components near similar temps. There’s also less of a chance to leak from less lines and something in the nose that can get punctured from road debris. The problem with the 2018-2021 expeditions is that Ford runs the engine so hot for emissions that it’s gets the trans too hot as well. The factory T stat cracks open at 195 and not fully open until about 220. I’m using a 180 T stat and the trans never goes above 190. With the factory 195, it was always around 210-215. On the other side of this, if you’re towing a lot, eventually the coolant temp will be high and drag the trans up since the F150’s and Expeditions have way too thin of a radiator. To fix that, a larger radiator as well as a lower T stat is needed. I’m not towing so lucky to be getting by with 190 temps. One big draw back I can see though with a coolant to trans oil exchanger is if coolant does leak into the trans or vice versa, it’s expensive to fix and can damage a lot of parts pretty quick.

Would you please let me know the 180 thermostat part number? Thanks.

 

[Hellwig]

What you listed is the 190deg thermostat. I am curious what the part number is people are using for the 180deg? The thermostat number RT-1252 is also the same as HL3Z8575B, both are 190deg thermostats and yes you should also buy a new gasket to use when doing this, don't reuse the old gasket.

It does look like this is fairly easy to replace but you will lose 1-1.5 gallons of coolant when doing it, so make sure to buy some of that special ford yellow coolant.

I tried hard to find the part number for factory 180 thermostat but failed. I guess 180 thermostat is an aftermarket part, like SPD Performance.

--- It seems I find it: BR3E-8575-BB or RT1258

 

[BMW2FORD]

Would you please let me know the 180 thermostat part number? Thanks.

I bought an SPD part a while back before Ford came out with the updated part. I noticed it’s just a Ford BR3Z 8575 EE re boxed. Look for BR3Z 8575 G and that’s the new style for 180 degrees with the plastic end version to prevent binding.

 

[Hellwig]

I bought an SPD part a while back before Ford came out with the updated part. I noticed it’s just a Ford BR3Z 8575 EE re boxed. Look for BR3Z 8575 G and that’s the new style for 180 degrees with the plastic end version to prevent binding.

View attachment 77224

Thanks a million!

 

[JExpedition07]

I had this argument with guys on the forum a few years ago. A liquid cooled transmission heat exchanger is a bad idea, and I’m not particularly happy about it now having a 10R80. Love the transmission, but an air to liquid cooler is vastly superior to this setup. Newer =/= better but unfortunately a lot of guys don’t understand that. The HD tow pack used to include a 7 row cooler in the 5.4 Triton trucks. You never saw over 200 on those 6R80’s…and none of them blew out clutch drums either, but that’s a seperate discussion.

 

[duneslider]

I had this argument with guys on the forum a few years ago. A liquid cooled transmission heat exchanger is a bad idea, and I’m not particularly happy about it now having a 10R80. Love the transmission, but an air to liquid cooler is vastly superior to this setup. Newer =/= better but unfortunately a lot of guys don’t understand that. The HD tow pack used to include a 7 row cooler in the 5.4 Triton trucks. You never saw over 200 on those 6R80’s…and none of them blew out clutch drums either, but that’s a seperate discussion.

I think it is fine if it is done right. If the radiator were bigger and could handle the load then maybe it would be fine. I agree though and think that it would have been better to have an air to liquid cooler, or just add that if you have the tow package like the Raptor has both. Still not sure if there is a way to add the air to oil cooler like the raptor has/had?

Ford has done this a fair amount I believe. I think the 6.0 power stroke had some sort of an internal liquid/oil heat exchanger to cool the turbo oil or something like that and it had issues but I don't recall exactly what they were.

I also understand it for helping warm the transmission up quicker to get to operating temps faster but I still think an option to add the air to oil cooler should be there for the Towing applications.

 

[Hellwig]

I think it is fine if it is done right. If the radiator were bigger and could handle the load then maybe it would be fine. I agree though and think that it would have been better to have an air to liquid cooler, or just add that if you have the tow package like the Raptor has both. Still not sure if there is a way to add the air to oil cooler like the raptor has/had?

Ford has done this a fair amount I believe. I think the 6.0 power stroke had some sort of an internal liquid/oil heat exchanger to cool the turbo oil or something like that and it had issues but I don't recall exactly what they were.

I also understand it for helping warm the transmission up quicker to get to operating temps faster but I still think an option to add the air to oil cooler should be there for the Towing applications.

The only purpose of using heat exchanger to warm up tranny quickly is to increase a tiny amount of MPG on Ford's paperwork and then to please EPA. Nothing else. It doesn't bring anything good for customers in reality.

 

[manuelb]

The updated version of the standard thermostat makes both the engine and transmission run about 10 degrees cooler than stock. I haven’t run it in the summer yet, but I live in south Florida so 85°f is common in the winter. Both the engine and transmission now stay under 200°f.

Did you change the thermostat? The one that opens at 160 f?

 

[JimmyM]

I tow a 6500# camper a lot during the summer. This was the first summer with the 2023. I watch my coolant and trans temps (Using Torque Pro) and I don't think I've seen them over 200-205. If they were even close to 215-220, that thing would be getting an aux trans cooler one way or another.