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

[Hellwig]

Overheated fluid always harms transmissions. How much Ford can save from replacing the air to oil external tranny oil cooler with the heat exchanger? Most recent Suburban still has the air to oil transmission cooler, while Expedition doesn't. Meanwhile, it seems current gen 13 suburban has much less complaints on their 10L80 transmission.

 

[Squark]

I recently traded my Expedition Max for a new Yukon XL. I noticed the Yukon transmission runs cooler. I'm sure Ford engineered the fluid and transmission to handle the heat, but there's a significant difference. My Expy would sit around 210F in town and go up when towing. The Yukon sits between 145-155F in town and around 187F when towing our 7,600lb travel trailer. I've only had it since January, so I'm not sure what the summer temps will look like. I don't know if that makes any difference; it was just something I noticed.

 

[BMW2FORD]

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.

 

[5280tunage]

On this cooling discussion, on thing I just noticed this last weekend while troubleshooting a popping/rattling issue, I took the cowl off the top of the grille, which allowed me to look in, on the top of the radiator/coolers. I should have taken a picture of it but I failed to. First, between the two radiators (I have the HD tow), there was large amounts of cottonwood and airborne objects stuck between the two radiators. Given that there's like an inch between them, I see no way to effectively clean that, so I'm guessing it's reduced efficiency.

Also, the smaller of the two radiators, likely the tranny cooler, is this insanely thin and flimsy plastic one. Felt like a complete piece of junk, was kind of nerve wracking.

 

[duneslider]

There is not a dedicated transmission cooler. I am guessing what you were seeing was either the radiator and the AC? The engine coolant goes back to a heat exchanger at the transmission. No dedicated cooler for the transmission. I understand that the raptor has the heat exchanger AND an external oil cooler of some sort.

I am curious about this 180deg T-stat. I might need/want to try this. I need to look at where its located and see how hard it is on these.

 

[5280tunage]

I have had an SPD tstat in a box for over a year. Based on what I see, it's a pain. Was going to wait for a coolant flush or something before having someone throw it in for me.

And yeah, I just finally found it, it is the condenser. I really wish there was more room between these to try and give us a chance to clean them. I'd even like to be able to just blow them out in reverse but the fan assemblies are in the way for that. Just thought of a cool idea, wish these guys had a maintenance mode that let you reverse the fan polarity and/or direction to try and clean them out a bit.

 

[BMW2FORD]

It’s actually really easy. Follow the lower drivers side lower radiator hose to the engine and you’ll see a plastic housing with 3x 8mm bolts. One is sort of hard to see one of the 3x on the inner side. T stat is located in that housing and pops right out. The radiator has a drain on the drivers side as well and only about a gallon will come out then pull the three 8mm leaving the hose still attached and change the T stat. The 180 is a big improvement. I’ve never tuned my car and no problems with it and still plenty of heat even through New England 10 degree winters.

 

[5280tunage]

Wow, funny, I was looking for the more traditional location higher up, on the hose headed to the radiator. thanks for the notes, I'll look at it. Question though, does this effect the louvers for example? See, the thing is, in my mind, if you were doing a decent job of making these systems dynamic, the engine temp should play a role (at least through an algorithm) in the louver positioning. I clearly have no idea what Ford has used as a job number 2 design for the cooling behavior and the aerodynamics, so thought I'd pose that question.

 

[BMW2FORD]

There’s a lot of things that baffled me about the cooling system in these trucks but it all looks like Ford wants them to run really hot for emissions. I worry about 220f or more. The old Gen 1 engines lasted a long time but they stayed around 190-195. They seemed to have wanted the Gen 2’s to run hotter but the jury is still out on the Gen 2’s and if this is good or not since most are around 80k at this point. To start, the thermostat is on the lower cold side hose which is pretty crazy. Even the Ford service manual states due to that it’s a slower responding t stat. I’ve programmed the temp numbers to be above the bar graph on the gauges so I can see the coolant temp and it’s amazing how on acceleration it will swing upwards an easy 10 degrees but then that brings up how the temp is measured. On these Ecoboost engines, the engines coolant temp sensor is in the head metal to sensor - not coolant so no buffering. Some cars have a sensor in coolant and another metal to metal that work together but these only have one at the rear of the pass side head so that brings in a whole different way to measure coolant. As far as the radiator blinds, as soon as I installed the 180 T stat I thought they would negate what I did but what’s funny is it looks like they stay closed for warm up until about 170 degrees then just find fixed positions according to road speed and not really coolant temp. I couldn’t believe the blinds were that simple and just let my truck act like it had a lower temp overall after 170. I really like the 180 T stat and see Ford does use it in a lot of their police / taxi Ecoboost 3.5 engines.

 

[wakeboarder]

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.