Transmission overheating

[mhechtkopf]

I’m at a loss here. Dealership has worked on my Expedition multiple times and still same issue. I own a 2019 Ford Expedition. I have a few issues.. one issue is the shifting just isn’t smooth and slips and hard shifts a lot. Other and main issue is when I drive 70mph or higher speed for 1 hour or more my truck will shift really hard almost like hitting a speed bump @70mph! truck will do a crazy hard shift then you will see trans temp increase and minutes later fluid blows out the relief valve and you can see on back window glass and tailgate… trans temp increases to around 265-270ish then slowly decreases. This doesn’t happen when driving highway speeds of 55-65mph for same time… only over 70mph for 1hr or so. Once fluid blows out it won’t overheat again but runs hot, 210-215. Ford dealership has now reprogrammed, replaced parts 2 different times, replaced trans oil cooler, and now they have replaced transmission! First time I drove after new transmission was installed and over 70mph same thing occurred! Anyone else having this issue? Any help would be awesome! Thanks to all!

 

[East-TN]

What is the temp of your engine doing? Have they replaced the old thermostat? The old thermostat is known for sticking and causing problems for the engine and transmission. The engine thermostat was redesigned in 2022. Do a search on thermostat and you'll see multiple threads on the subject.

 

[mhechtkopf]

Ok great. Thanks for that info. When transmission is overheating and running hot… hot enough where numbers appear above gauge.. engine temp showing normal middle of gauge. I’ll say something to dealership. Appreciate the help!

 

[Dice Roll]

There has been some mention of a transmission thermostat that holds up the fluid from getting cooled until it hits a certain temp. I believe it’s in a line outside the trans. I dont have anything else for you, but it’s worth exploring.

 

[mhechtkopf]

Ok great. Thank you for that info! I’ll def look into it. Weird that the dealership hasn’t run into this issue before!

 

[Dice Roll]

You might dig into past posts on here. I know I saw it on here. Seems a guy was traveling and the trans stat messed up and he was overheating it. Might’ve been the line it is in is replaced as an assembly.

 

[mhechtkopf]

Ok thanks. I’ve been trying to figure it out! Trans oil cooler has been replaced, multiple reprogramming, replaced parts 2 different times, and it now has a new transmission. I’m going to keep searching like you said. Thanks for helping! Appreciate it!

 

[chongo]

While your issues are quite different than what I experienced, here is what I experienced, did and the changes I saw.
FIrst, I’ve run a Livernois Tune (Premium) for the life of the vehicle with their trans tuning. I had to replace my trans around 75k miles in my 2019. After I replaced it and the trans cooler and a few other parts, I started to watch my trans temp more closely and noticed in regular driving the trans temp would quickly get up to 220-225 and spirited driving or pulling a flatbed with a side by side on it, it would jump to 235+. Hot enough the trans temp would display on the dash.
I replaced the thermostat with a SPD 170 degree stat and I never say my trans temp exceed 208. Regular driving it trans temp would be in the 180-190 range, even in the hot Texas summers. Spirited or towing 200-208. Now, my understanding is the thermostat should not affect the trans temp but it did and I’ve read others comments that they had the same experience. If you haven’t swapped out the OEM unit, it’s $65 shipped from 5star Tuning and about 30 min of time. It’s worth trying. I hope this helps.

 

[mhechtkopf]

Ok awesome! I keep reading about changing thermostat and think it’s worth a try for sure! And I’ll def prob order that tuner you are talking about. It’s just wild how temp spikes when driving around 70mph for an hour or so then trans fluid comes out relief valve. Either way always runs hot.. thanks for the help!

 

[Calidad]

2018-2022 the thermostats were trash. Ford quietly redesigned them. I had similar issues but caught it before it got that bad. The old thermostat fails slowly and first shows up in hot transmission temps. Eventually spiking the coolant temp.

Normal transmission temps no trailer id 183-201 on the highway. Towing the 8700lb boat 190-210 with temp cooling down quickly. For example heavy stop and go traffic with 8700lbs of boat basically worst situation for transmission temp I saw it hit 214 and it immediately dropped to 205 while climbing a decent grade at 2300rpm and 40mph. Prior to the new thermostat temps were hitting 230 and getting it to cool down were nearly impossible.

The F250 I just borrowed 6.8L gas 6spd ran 190-205 trans temp hauling the boat 190 miles 0-7400ft pass. Might try the Expedition next yr. Last yr the Expedition was definitely suffering early cooling issues during that haul and I had a buddy come get the boat at 5400ft given I couldn’t get temps to drop even with 30 minutes of idling in the side of the road.

The thermostat issue vs heat exchanger setup for the transmission causes this temperature issue to first appear in the transmission temperature.
Updated thermostat part in package picture. Its a 190 temp thermostat. Total game changer having a $40 part working correctly. Its a 1hr shop job $40 part. Easy fix. I did fight with my dealer they tried to soak me for $850. I have a warranty!!! I said no thanks I’ll have a trusted shop do it and file a claim with Ford. “oh!! Your a preferred customer $100 deductible it will be done in an hour! No joke… Fing crooks.. My warranty is $100 deductible which I figured would be the case regardless.

I was fully ready to have my local guy do it and file a claim with Ford. Had I done this Ford would have asked why I didn’t have the dealer 6 miles away do it. I would have told them they refused warranty work and quoted me $850 for a $40 part and hour shop time. Which case Ford would have reimbursed me then called the dealer to ask why they can’t service Ford vehicles with warranties or at actual shop rates.. IE the dealer would look very bad…

 

[mhechtkopf]

Awesome! Thank you! I’m going to see if they will do it under warranty… they may go ahead and do it since they have worked on trans so many times. If not I’ll replace myself. Pretty easy job overall. Appreciate the help!

 

[ms136]

My "new" transmission was venting only when towing a camper and running around 220F. I found that the installing dealer had overfilled it by one quart according to the dipstick. After drawing out that quart, no more venting and trans temp reduced about 5F under the same towing conditions.

 

[Dice Roll]

My dealer did the stat for 130 bucks total on top of the flush. It was due for a flush and the stat was giving up so it was a no brainer. If it’d been much more I’d have done it myself.

 

[ZigZagFred]

Many of the threads I've seen on this forum have suggested replacing the thermostat to address any overheating issues. It would seem to be a good, inexpensive (relatively) easy first step.

 

[T Bird]

my understanding is the thermostat should not affect the trans temp

I've read the opposite- the tstat has a big impact on tranny temp

 

[Hellwig]

I've read the opposite- the tstat has a big impact on tranny temp

Here is my experience since I replaced it only a couple of weeks ago. After the replacement, the tranny temp still slowly goes up to 210F during long drives (more than 30 minutes runtime with ambient temp around 70F). But it only hits 210F very briefly and then drops fast to 190Fish. My theory is there is a temp sensor somewhere in the tranny fluid heat exchange box. Only after the fluid temp climbs upto 210F, the sensor gives signal to open some valve(s) in the heat exchange and then engine coolant starts to cool the tranny fluid. Because the engine coolant is "colder", it cools tranny fluid more than what it could do before the replacement. My tranny working temp used to be from 205F to 210F. Now the working temp is below 200F.

 

[mhechtkopf]

Ok. I appreciate that info and help. I’m working hard to try and figure this issue out. Very frustrating.

 

[F250Pilot]

Here is my experience since I replaced it only a couple of weeks ago. After the replacement, the tranny temp still slowly goes up to 210F during long drives (more than 30 minutes runtime with ambient temp around 70F). But it only hits 210F very briefly and then drops fast to 190Fish. My theory is there is a temp sensor somewhere in the tranny fluid heat exchange box. Only after the fluid temp climbs upto 210F, the sensor gives signal to open some valve(s) in the heat exchange and then engine coolant starts to cool the tranny fluid. Because the engine coolant is "colder", it cools tranny fluid more than what it could do before the replacement. My tranny working temp used to be from 205F to 210F. Now the working temp is below 200F.

This is correct. I have a 2024 F250, and it, too, has a heat exchanger down near the transmission. On a cold start, engine coolant heats up faster than the transmission fluid, so this coolant valve is open during a cold start, and coolant flows to the heat exchanger, heating up the transmission fluid. For fuel economy, they want that fluid to heat up as fast as possible. Eventually, the two fluids are the same temperature, and the coolant valve closes and allows the transmission to get hotter. 220 is the normal unloaded temp for my 10R140. This coolant valve modulates to keep the transmission around 220 with the 195-degree coolant. My coolant runs around 195. So the heat exchanger job is to first heat up the oil, and then cool the oil.

I want the transmission to run cooler, so I bought a 3/4" 90-degree brass barbed adapter and disconnected the two coolant hoses that pass through the PCM-controlled coolant valve. I inserted the brass adapter, so now my coolant flows 100% of the time through the heat exchanger, bypassing the coolant valve. My transmission temp is 25 degrees less and now runs at 195, like my coolant. I left the PCM-controlled coolant valve in place so the computer logic is still there, and no codes are thrown.

I just bought a new 2024 Expedition Max Limited and drove around checking the transmission temp and coolant temp with my Forscan laptop. Eventually, the transmission was running about 215, and the coolant was 195-200. The coolant valve that sends coolant to the heat exchanger is low right in front of the motor. On this one, I bought a straight 3/4" barbed adapter, and I'm fitting it this morning. You use 2 pliers that are made to pinch coolant hoses. Pinch each hose going into the coolant valve and slide the pinch clamps down, and insert the new barbed adapter. Now the coolant flows 100% of the time to the heat exchanger, and you knock 20 degrees or so out of the transmission fluid. I also put plastic plug caps over the two barbed fittings on the coolant valve to keep dirt out, in case I want to put it back.

 

[Hellwig]

This is correct. I have a 2024 F250, and it, too, has a heat exchanger down near the transmission. On a cold start, engine coolant heats up faster than the transmission fluid, so this coolant valve is open during a cold start, and coolant flows to the heat exchanger, heating up the transmission fluid. For fuel economy, they want that fluid to heat up as fast as possible. Eventually, the two fluids are the same temperature, and the coolant valve closes and allows the transmission to get hotter. 220 is the normal unloaded temp for my 10R140. This coolant valve modulates to keep the transmission around 220 with the 195-degree coolant. My coolant runs around 195. So the heat exchanger job is to first heat up the oil, and then cool the oil.

I want the transmission to run cooler, so I bought a 3/4" 90-degree brass barbed adapter and disconnected the two coolant hoses that pass through the PCM-controlled coolant valve. I inserted the brass adapter, so now my coolant flows 100% of the time through the heat exchanger, bypassing the coolant valve. My transmission temp is 25 degrees less and now runs at 195, like my coolant. I left the PCM-controlled coolant valve in place so the computer logic is still there, and no codes are thrown.

I just bought a new 2024 Expedition Max Limited and drove around checking the transmission temp and coolant temp with my Forscan laptop. Eventually, the transmission was running about 215, and the coolant was 195-200. The coolant valve that sends coolant to the heat exchanger is low right in front of the motor. On this one, I bought a straight 3/4" barbed adapter, and I'm fitting it this morning. You use 2 pliers that are made to pinch coolant hoses. Pinch each hose going into the coolant valve and slide the pinch clamps down, and insert the new barbed adapter. Now the coolant flows 100% of the time to the heat exchanger, and you knock 20 degrees or so out of the transmission fluid. I also put rubber plug caps over the two barbed fittings on the coolant valve to keep dirt out, in case I want to put it back.

Excellent idea.

 

[demcpita]

This is correct. I have a 2024 F250, and it, too, has a heat exchanger down near the transmission. On a cold start, engine coolant heats up faster than the transmission fluid, so this coolant valve is open during a cold start, and coolant flows to the heat exchanger, heating up the transmission fluid. For fuel economy, they want that fluid to heat up as fast as possible. Eventually, the two fluids are the same temperature, and the coolant valve closes and allows the transmission to get hotter. 220 is the normal unloaded temp for my 10R140. This coolant valve modulates to keep the transmission around 220 with the 195-degree coolant. My coolant runs around 195. So the heat exchanger job is to first heat up the oil, and then cool the oil.

I want the transmission to run cooler, so I bought a 3/4" 90-degree brass barbed adapter and disconnected the two coolant hoses that pass through the PCM-controlled coolant valve. I inserted the brass adapter, so now my coolant flows 100% of the time through the heat exchanger, bypassing the coolant valve. My transmission temp is 25 degrees less and now runs at 195, like my coolant. I left the PCM-controlled coolant valve in place so the computer logic is still there, and no codes are thrown.

I just bought a new 2024 Expedition Max Limited and drove around checking the transmission temp and coolant temp with my Forscan laptop. Eventually, the transmission was running about 215, and the coolant was 195-200. The coolant valve that sends coolant to the heat exchanger is low right in front of the motor. On this one, I bought a straight 3/4" barbed adapter, and I'm fitting it this morning. You use 2 pliers that are made to pinch coolant hoses. Pinch each hose going into the coolant valve and slide the pinch clamps down, and insert the new barbed adapter. Now the coolant flows 100% of the time to the heat exchanger, and you knock 20 degrees or so out of the transmission fluid. I also put plastic plug caps over the two barbed fittings on the coolant valve to keep dirt out, in case I want to put it back.

I have a 2019 expy limited that the trans is running 220 and would like to do this bypass. Could you provide anymore info on how you did this? TIA