Transmission got hot - fluid everywhere

[kep5niner]

Driving on the highway for a 3-hour trip, and about 30 minutes remaining, my trans temp got very hot (I saw 232*). The cruise was set for most of the trip, relatively flat terrain (Missouri), and I was not towing. Ambient temperature was a little over 80*. I’ve got about 80k miles on my Navigator. Trans was just serviced, to include dropping the pan and new filter, last year at 67k miles shortly after I bought the truck.

After pulling over to let the trans cool down, I noticed trans fluid all over the underside of the truck. Of course there’s no easy way to check the fluid level. Still covered under warranty, I took it easy and got it to a Ford dealership about 20 miles away, monitoring the temp which didn’t exceed 190*.

The Ford dealership stated the pan gasket was bad and there was an obstruction in the oil cooler. New cooler, replaced pan gasket, and she’s back on the road.

Something doesn’t add up. Which came first - the chicken or the egg? Did something fail, thus generating the excessive heat and the subsequent overflow, or did the trans just leak, lose fluid and get hot because of the low fluid level?

I know it’s hard to troubleshoot from the keyboard, but it doesn’t seem like the dealership’s solution may have addressed the underlying problem. Anyone have any experience with this or any other ideas? She’s under the Lincoln Protect ESC for another 4 years / 70k miles, so I’m not losing sleep over this, but don’t need to have another mission jeopardized by an unreliable truck.

 

[Grrumpy]

If, and I say If the cooler flow was blocked by an obstruction, it would not let fluid flow/cool, probably leading due to the over heating,.,,,maybe causing the gasket to fail.
Is this the first time you have towed since getting it or first time towing since the trans was serviced ? Asking as if it is the first time, than everything else has been solo and the fluid may not have heated enough to cause a problem.
Also, wondering what kind of an obstruction was found "inside" the cooler and where did it come from....filter or metal pieces/debris ????

 

[kep5niner]

I was not towing, and I probably won’t tow anything with this. That’s what the Super Duty is for. The trans was serviced 13,000 miles ago. I had every fluid serviced after I took possession of the Navigator, for a known benchmark.

 

[Grrumpy]

I am still curious what the technician found that was "blocking" the cooler. Any obstruction would be an obvious clue as to the fluid overheating.....maybe causing the gasket to leak or a hose to leak....

 

[99WhiteC5Coupe]

Driving on the highway for a 3-hour trip, and about 30 minutes remaining, my trans temp got very hot (I saw 232*). The cruise was set for most of the trip, relatively flat terrain (Missouri), and I was not towing. Ambient temperature was a little over 80*. I’ve got about 80k miles on my Navigator. Trans was just serviced, to include dropping the pan and new filter, last year at 67k miles shortly after I bought the truck.

After pulling over to let the trans cool down, I noticed trans fluid all over the underside of the truck. Of course there’s no easy way to check the fluid level. Still covered under warranty, I took it easy and got it to a Ford dealership about 20 miles away, monitoring the temp which didn’t exceed 190*.

The Ford dealership stated the pan gasket was bad and there was an obstruction in the oil cooler. New cooler, replaced pan gasket, and she’s back on the road.

Something doesn’t add up. Which came first - the chicken or the egg? Did something fail, thus generating the excessive heat and the subsequent overflow, or did the trans just leak, lose fluid and get hot because of the low fluid level?

I know it’s hard to troubleshoot from the keyboard, but it doesn’t seem like the dealership’s solution may have addressed the underlying problem. Anyone have any experience with this or any other ideas? She’s under the Lincoln Protect ESC for another 4 years / 70k miles, so I’m not losing sleep over this, but don’t need to have another mission jeopardized by an unreliable truck.

From afar - if the transmission fluid cooler had an obstruction, it had to come from inside the transmission.

I suspect with the overheat, fluid loss, and obstruction in the cooler - that you will have more problems soon with the transmission.

 

[kep5niner]

Figured as much.

 

[3rd Expyowner123]

Had transmission fluid changed out with new filter on my 2018 Expedition a couple years ago around 70k miles. Perhaps 6 months afterwords while towing our 21’ boat on the freeway in hot weather my transmission started to approach 230. My transmission had never gotten this hot before under similar conditions. The route we were on required exiting the freeway onto a state highway. After turning at almost idle speed and resuming to highway speeds the transmission cooled down quickly. I have no explanation. Later around 100k miles had ESP warranty overhaul replacing CDF drum and an redesigned internal outer casing for hard shift into 5th and hard engagement into reverse. Now at 107k miles transmission is a little wonky shifting into 5th gear but working fine in all other aspects.

 

[heyjay]

I would add that a transmission temperature of 232 is not necessarily problematically hot with these transmissions but I would say it’s abnormal given the conditions you were driving in. They do run warmer than many others. There is no transmission cooler line other than it comes through a small block at the front of the transmission and passes by a coolant line. If there’s any problem with your coolant system then there is a higher risk of the transmission temp climbing.

 

[LT-EXPO]

For reference: I just crossed over 165k miles-2018 Expedition XLT 4x4 HD Tow package. AAMCO Changed fluid/filter around 120k which helped a little with the sleeve issue allowing me to get original trans to 165k. Was on highway drive (1 hour) in MN -NOT TOWING, flat area and trans got up to 230, shifted like it was pushing through resistance with faint clicking noise. I got home, smelling trans fluid, parked, next day had small leak. AAMCO checked codes & leak & said it’s time to replace it.
Almost $9K later-3 year/100k warranty-Remanufactured unit in-back on road..Trans got to 225 & smelling like fluid. AAMCO replaced pan gasket-warranty work done & back on road-no issues. Temp never gets much over 190 unless I am on extended drive or trailer work. Keep an eye on temp it’s been my best indicator of low fluid.
To make me feel better a neighbor told me his Audi brake job costs $$8k
I’ve done the upgrades on cam-phasers, and all new plastic pieces involved, & new chassis upgrades so somewhat confident it’s going to last since I’ve replaced a lot-Run Bilstein 5100’s, Cooper Road & Trail XL tires-Stock 20’s, ritually keep diffs/transfer case fresh. Figure I can keep it going forever & upgrade parts as needed! Aluminum body is holding up well in the rust belt, just keep it clean & prevent frame rust! Cheers

 

[EricVee]

On my 2019 Expedition I noticed the transmission temperature running quite High. I also noticed the cooling fans were running a lot more frequently. Thanks to this forum I learned that the engine might still be running hotter because there's issues with the engine thermostat. So, even though it's getting too hot, after the engine warms up the temperature gauge remains right in the middle as it has from the day it was brand new. I found the thermostat was indeed obstructed by some rubber material that was part of it. It was falling apart. After replacing the thermostat with the Ford redesigned version, the transmission temperatures run nearly 20° lower and I haven't heard the cooling fans run very much at all. I have a feeling that the coolant temperature gauge always hovers in the middle until there's a significant overheating event and then it will jump to the hot end of the range. I don't recall where I saw it, but I know I've seen a temperature gauge on another vehicle that works in that way. Of course, since the transmission fluid is cooled by the engine coolant, hot coolant will make the transmission run hotter.

 

[CharlieJ]

I had this issue while towing after my trans fluid was changed. Turns out they overfilled it. I also changed my engine thermostat to 180. Now it never gets over 210 even when towing up mountains. Most of the time it runs around 190.