19 strange running hot issue.

[UstonXpedition]

2019 Max,
New: RT1258 Thermostat
Water pump (Dayco)
Heater hoses (Ford)
Upper radiator hose (ford)
Belts (Gates/ford)
Spark plugs(NGK)
Added: Aftermarket Transcooler

We left Houston heading to Colorado. She ran great From Houston, to border of New Mexico. Once we got into New Mexico Transmission started to delay shifts into 8-9-10 Normal mode/sports mode. I reset the adaptive learning and stopped it. It would still delay the shift. Then would start running hot when ECT would start hanging around 228-235. on flat land. But once it shift into 10 and running straight ECT would be 185-195 and stay. Once I had to slow down and pickup speed again. The delay shift and engine temp would rise again. Mind you. The trans temp was at running 159-177f the whole time. Trans was not overheating. When I hit the mountain's it would start to get to 235f. So I slowed it down. Once I got to Colorado springs I had a shop diagnose it and a could not figure out the situation. We changed the thermostat, flushed the coolant. Everything was fine. So we keep going. On our way to Denver it engine would start to heat up again when shifting into 8-9-10. Made it to Denver and had a very reputable shop try to diagnose it. They ran A block test to see if my head gasket was bad. Everything was good. They could not find the problem also. Now I'm forced to ship the vehicle back to Houston because we have no conclusion on what the problem can be.
Would a bad 10r80 cause engine to overheat? Also there is still a slight misfire at idle. I changed the plug to NGK and still has a slight misfire. Would the misfire cause it overheat? I'm stuck on what else to look at. Any advice would be greatly appreciated. Thanks in advance

 

[DieselMonk]

Ignore the tranny for now and work on your misfire.

 

[East-TN]

Did you have any of these problems before you added the aftermarket trans cooler? What kind and brand of trans cooler did you add? Is it blocking any airflow? Is it tied into the engine coolant or air cooled?

Maybe remove the aftermarket trans cooler, go back to stock and see if that fixes the overheat issue.

And definitely see what's causing the misfire.

 

[Bmac1955]

I have a question regarding trans. How does it upshift when cold? Any delay in shifting when cold and clears up only to return after sitting over night? I had similar issues. Terrible gas mileage, erratic shifts when cold, to ME high temps and lacking the ability to get into 10th gear. Took in to ford to have the issue checked. Left the vehicle overnight for them to experienced the cold erratic upshift and found a lose of pressure creating the problem. I don't understand the full functions of the internals of the 10R80 trans but after the complete over haul of the trans problems are gone. I have put maybe 700 miles on it and it cycles thru all the gears with no issues. Temps have been fine also. Just my experience.

 

[UstonXpedition]

Did you have any of these problems before you added the aftermarket trans cooler? What kind and brand of trans cooler did you add? Is it blocking any airflow? Is it tied into the engine coolant or air cooled?

Maybe remove the aftermarket trans cooler, go back to stock and see if that fixes the overheat issue.

And definitely see what's causing the misfire.

No problems before but the rough shift from 3-5 and trans overheating once when towing. But when I did all the maintenance and the cooler mod. It was fine in houston with 98f ambient temp. No problems with tranny temp or engine temp. The problem started when it would delay shift. But never had the transmission over heat or go over 177f. Im leaning torwards the rought idle because I know. These 3.5 with a small misfire will run bad. Even with no code.

 

[UstonXpedition]

I have a question regarding trans. How does it upshift when cold? Any delay in shifting when cold and clears up only to return after sitting over night? I had similar issues. Terrible gas mileage, erratic shifts when cold, to ME high temps and lacking the ability to get into 10th gear. Took in to ford to have the issue checked. Left the vehicle overnight for them to experienced the cold erratic upshift and found a lose of pressure creating the problem. I don't understand the full functions of the internals of the 10R80 trans but after the complete over haul of the trans problems are gone. I have put maybe 700 miles on it and it cycles thru all the gears with no issues. Temps have been fine also. Just my experience.

No problem when cold. It just randomly started to delay shift during or trip. Transmission fluid was black when I changed it. So I guess it was never serviced.

 

[UstonXpedition]

Im still stuck on what else I see can cause the over heating. Im at either the radiator is clogged, or the auxiliary water pump has failed. (I did get a flush of the cooling). I don't know if that would also unclog/clean the radiator.

 

[DieselMonk]

Isn’t the auxiliary water pump (electric) only supposed to work when the engine is not running or idling? I don’t think it runs while driving on the highway. Maybe it supposed to kick in to help the water pump if it’s hot out and it doesn’t?

 

[Calidad]

Faulty thermostat first affected the stock transmission setup the most causing high transmission temps. Eventually the sticking tstat will cause a engine temp spike.

Two things the radiator blocked by the additional trans cooler is a factor. Hard to say if the thermostat is an issue given the extra transmission cooler.

Cold transmission behavior in my 19 has never been different than being at temp. However if the transmission was repaired but pump assembly wasn’t replaced common Ford warranty repair it’s possible the transmission is still screwed up with debris.