Transmission temperatures

[Linksvu]

Hey all, I’m hoping for some education or insight on transmission temperatures and cooling. I have a 2017 EL with the towing package that is used a lot, mostly mountain driving but then towing a few times a year. Over the last five years I have seen a change in the average temperature readings for the transmission and I’m wondering if there is a reason or something that can be done about it. Ultimately, I would like to keep this transmission healthy into the upper 200s.

I regularly watch the oil pressure, oil temp, trans temp screen. When we first got the expedition six years ago, it had 90K on it. For those first few years, the transmission temperatures almost always stayed within the upper 190s, say 196–198. Clearly there were sometimes it rose, but I do not believe I ever saw higher than 206.

Then about three years ago, when I had the fluid and filter changed, it started to consistently run in the low 200s, 202–206. Now, after doing another filter and fluid change, it is consistently running 206–210, and I’ve even seen 212.

So, two questions: how does the transmission cooling system work? Any thoughts or ideas of why my average temperatures might be climbing?

On the first one, I’m wondering if any inefficiency in my engine cooling may be contributing. Could it be things like the water pump or the radiator affecting the temperatures of the trans cooler?

On the second one, I’m wondering if choices in fluids, filters, or changes versus flushes might be making a difference.

Thank you for your help!

 

[GlennSullivan]

Interesting that you mention this. I also have a 2017 HD Tow. Just turned 60,000 mi. Trans temp never went over 202 until I had the fluid and filter changed (full flush) early this year at 55,000mi.
On a recent 1800 mile run to Chicago and back not towing but with lots of mountainous terrain and stop and go driving in very warm temps (RT80 construction is a total nightmare) I'm now seeing up to 205 at certain times, which had me wondering.

 

[99WhiteC5Coupe]

Hey all, I’m hoping for some education or insight on transmission temperatures and cooling. I have a 2017 EL with the towing package that is used a lot, mostly mountain driving but then towing a few times a year. Over the last five years I have seen a change in the average temperature readings for the transmission and I’m wondering if there is a reason or something that can be done about it. Ultimately, I would like to keep this transmission healthy into the upper 200s.

I regularly watch the oil pressure, oil temp, trans temp screen. When we first got the expedition six years ago, it had 90K on it. For those first few years, the transmission temperatures almost always stayed within the upper 190s, say 196–198. Clearly there were sometimes it rose, but I do not believe I ever saw higher than 206.

Then about three years ago, when I had the fluid and filter changed, it started to consistently run in the low 200s, 202–206. Now, after doing another filter and fluid change, it is consistently running 206–210, and I’ve even seen 212.

So, two questions: how does the transmission cooling system work? Any thoughts or ideas of why my average temperatures might be climbing?

On the first one, I’m wondering if any inefficiency in my engine cooling may be contributing. Could it be things like the water pump or the radiator affecting the temperatures of the trans cooler?

On the second one, I’m wondering if choices in fluids, filters, or changes versus flushes might be making a difference.

Thank you for your help!

I bought a new 2015 Expedition Limited 4x4 with the factory HD tow package. I never towed with it, only using it for passenger and light cargo use.

I often saw the transmission temperature about 196 - 198 degrees F, when driving with passengers and ambient air temperatures in the low 90’s F. No mountains - just some hills and flat roads.

I had the transmission fluid and filter changed (no flush) at about 60,000 miles - at a Ford dealer. The transmission failed at about 70,000 miles.

I bought a new 2024 Tahoe Premier 4WD with the towing package. The transmission temperature with the same vehicle usage is about 146 - 150 degrees F. It runs much cooler than the Expedition did. It has the 10-speed automatic transmission (the Expedition had the 6-speed transmission).

The Expedition transmission cooling system, with the HD towing package, had an air-to-fluid supplemental cooling radiator in front of the a/c condenser (behind the radiator grille - easy to see). Periodically, I would reach in and clear any bugs or debris from it. I also gently hosed it down when washing the vehicle by hand.

I always thought the Expedition transmission fluid ran too hot with just passenger use. At times, the two radiator cooling fans would runn very high RPM’s, creating a loud roaring sound. Even with the radiator fans on the extra-high speed, the transmission ran hot.

 

[Linksvu]

Interesting that you mention this. I also have a 2017 HD Tow. Just turned 60,000 mi. Trans temp never went over 202 until I had the fluid and filter changed (full flush) early this year at 55,000mi.
On a recent 1800 mile run to Chicago and back not towing but with lots of mountainous terrain and stop and go driving in very warm temps (RT80 construction is a total nightmare) I'm now seeing up to 205 at certain times, which had me wondering.

This is nearly identical to my experience too. Always 190s until the fluid was changed.

 

[Linksvu]

I bought a new 2015 Expedition Limited 4x4 with the factory HD tow package. I never towed with it, only using it for passenger and light cargo use.

I often saw the transmission temperature about 196 - 198 degrees F, when driving with passengers and ambient air temperatures in the low 90’s F. No mountains - just some hills and flat roads.

I had the transmission fluid and filter changed (no flush) at about 60,000 miles - at a Ford dealer. The transmission failed at about 70,000 miles.

I bought a new 2024 Tahoe Premier 4WD with the towing package. The transmission temperature with the same vehicle usage is about 146 - 150 degrees F. It runs much cooler than the Expedition did. It has the 10-speed automatic transmission (the Expedition had the 6-speed transmission).

The Expedition transmission cooling system, with the HD towing package, had an air-to-fluid supplemental cooling radiator in front of the a/c condenser (behind the radiator grille - easy to see). Periodically, I would reach in and clear any bugs or debris from it. I also gently hosed it down when washing the vehicle by hand.

I always thought the Expedition transmission fluid ran too hot with just passenger use. At times, the two radiator cooling fans would runn very high RPM’s, creating a loud roaring sound. Even with the radiator fans on the extra-high speed, the transmission ran hot.

So the trans cooler is behind the radiator? So, theoretically, if the radiator was running a bit warmer the trans cooler could run a bit warmer too?

 

[99WhiteC5Coupe]

So the trans cooler is behind the radiator? So, theoretically, if the radiator was running a bit warmer the trans cooler could run a bit warmer too?

It’s hard to say - but I don’t think so.

With the HD cooling package, a smaller “radiator” for only transmission fluid is mounted in the front grille airflow, mounted in front of the a/c condenser, which is mounted in front of the radiator (front to back).

If the radiator is running warmer, it should trigger a higher airflow using the two radiator cooling fans (mounted at the rear of the radiator). I don’t think much heat would transfer through the a/c condenser and into the transmission fluid radiator.

Using a flashlight, you can look through the front grille to see the HD transmission fluid radiator. It is on the right (passenger side) of the vehicle, and is about 5” x 10” x 1-2” thick.

For vehicles without a separate transmission fluid radiator (cars and trucks), the transmission fluid is routed (via tubing) through a side tank of the engine coolant radiator, and is cooled using the engine coolant (via a small tank inside the side of the engine coolant radiator).

When driving the vehicle at medium to fast speeds, the air in front of the vehicle is pushed through the transmission fluid radiator, a/c condenser and engine coolant radiator. The electric radiator fans often are shut-off or not run at high speeds due to the “ram air” effect of the incoming air.

 

[GlennSullivan]

It’s hard to say - but I don’t think so.

With the HD cooling package, a smaller “radiator” for only transmission fluid is mounted in the front grille airflow, mounted in front of the a/c condenser, which is mounted in front of the radiator (front to back).

If the radiator is running warmer, it should trigger a higher airflow using the two radiator cooling fans (mounted at the rear of the radiator). I don’t think much heat would transfer through the a/c condenser and into the transmission fluid radiator.

Using a flashlight, you can look through the front grille to see the HD transmission fluid radiator. It is on the right (passenger side) of the vehicle, and is about 5” x 10” x 1-2” thick.

For vehicles without a separate transmission fluid radiator (cars and trucks), the transmission fluid is routed (via tubing) through a side tank of the engine coolant radiator, and is cooled using the engine coolant (via a small tank inside the side of the engine coolant radiator).

When driving the vehicle at medium to fast speeds, the air in front of the vehicle is pushed through the transmission fluid radiator, a/c condenser and engine coolant radiator. The electric radiator fans often are shut-off or not run at high speeds due to the “ram air” effect of the incoming air.

Do you have any thoughts on what is causing these trans temp increases after a trans fluid / filter replacement? Your remarks got me thinking about the vehicles with HD tow, which the above owners including myself seem to have AND the possibility that the trans cooler equipped vehicles will require more fluid and dealers are installing the amount specified for standard vehicles and not actually checking the level - which of course is a PITA to do with no dipstick.

 

[99WhiteC5Coupe]

Do you have any thoughts on what is causing these trans temp increases after a trans fluid / filter replacement? Your remarks got me thinking about the vehicles with HD tow, which the above owners including myself seem to have AND the possibility that the trans cooler equipped vehicles will require more fluid and dealers are installing the amount specified for standard vehicles and not actually checking the level - which of course is a PITA to do with no dipstick.

I’m not sure what causes the temperature increases after a fluid / filter replacement?

Since the fluid change (not flush) is a gravity-drain method, by removing the pan and filter, I don’t think the transmission fluid radiator would drain?

But - if it did, then the proper amount of transmission fluid is added and verified after change, there should not be a low level of fluid with the HD cooling package.

Ford made it very difficult for an owner to check the transmission fluid level with the 6-speed transmission on the Expedition and Navigator, so most owner’s must rely on the the dealer technician to fill it properly.

I recall sometimes my transmission fluid temperature would reach about 203 degrees F while in 2WD with passenger use and no towing or heavy load (and no aggressive driving).

The owner’s manual did not give an explanation of what would be normal or abnormal for the transmission fluid temperatures. I always thought that was odd.

 

[GlennSullivan]

I’m not sure what causes the temperature increases after a fluid / filter replacement?

Since the fluid change (not flush) is a gravity-drain method, by removing the pan and filter, I don’t think the transmission fluid radiator would drain?

But - if it did, then the proper amount of transmission fluid is added and verified after change, there should not be a low level of fluid with the HD cooling package.

Ford made it very difficult for an owner to check the transmission fluid level with the 6-speed transmission on the Expedition and Navigator, so most owner’s must rely on the the dealer technician to fill it properly.

I recall sometimes my transmission fluid temperature would reach about 203 degrees F while in 2WD with passenger use and no towing or heavy load (and no aggressive driving).

The owner’s manual did not give an explanation of what would be normal or abnormal for the transmission fluid temperatures. I always thought that was odd.

At least in my case, I requested and paid for a full flush. This was done at a dealer that has worked on both of my Expeditions for about 5 years now.

I have a lift in my garage / shop, which is how I do my oil changes and other maintenance work. Not sure how I would check the fluid level as when the truck is in the air it is generally not perfectly level.

 

[chuck s]

Why the early service? The "me too" increased transmission temperatures tell me something has changed. Wrong fluid or changed spec?

I'm seeing the transmission oil change interval listed at 150,000 miles (page 444 of my 2017 owner's manual). BTW mine run a normal max of 200 - 202 towing or not, it doesn't seem to matter.

-- Chuck

 

[drscanman]

Why the early service? The "me too" increased transmission temperatures tell me something has changed. Wrong fluid or changed spec?

I'm seeing the transmission oil change interval listed at 150,000 miles (page 444 of my 2017 owner's manual). BTW mine run a normal max of 200 - 202 towing or not, it doesn't seem to matter.

-- Chuck

Mine too Chuck, 2017 with 141K, same tranny temp and conidtions.

 

[DeafBringer]

Those who had fluids changed and saw increase temps, are you able to confirm whether the correct spec transmission fluid were put in? They're getting harder and harder to find. And more expensive per bottle!

 

[GlennSullivan]

Those who had fluids changed and saw increase temps, are you able to confirm whether the correct spec transmission fluid were put in? They're getting harder and harder to find. And more expensive per bottle!

In my case a local Ford Dealer that I've been pleased with their work for the 5 years performed the service. In answer to why the early service, the same reason I change my oil at 3500-4000 instead of the recommended 7500-10000.

FYI. Here is 3500 mile oil coming out of my 2017 3.5 T/T after mostly highway driving with no towing. 4000 mile oil coming out of my 2011 5.4 N/A looks like it is coming out of the jug.

 

[99WhiteC5Coupe]

In my case a local Ford Dealer that I've been pleased with their work for the 5 years performed the service. In answer to why the early service, the same reason I change my oil at 3500-4000 instead of the recommended 7500-10000.

FYI. Here is 3500 mile oil coming out of my 2017 3.5 T/T after mostly highway driving with no towing. 4000 mile oil coming out of my 2011 5.4 N/A looks like it is coming out of the jug. View attachment 85193

My Dad used to say “Oil is cheap - engines aren’t”.

 

[GlennSullivan]

My Dad used to say “Oil is cheap - engines aren’t”.Turbos are brutal on oil. Running it up against the exhause literally cooks it.

Smart Man. Turbos really punish oil, it is that constant exposure to the high temp exhaust that hurts.

 

[Linksvu]

Those who had fluids changed and saw increase temps, are you able to confirm whether the correct spec transmission fluid were put in? They're getting harder and harder to find. And more expensive per bottle!

It’s a valid question. I’m not sure on mine. What’s the spec’d trans fluid?

 

[Linksvu]

Thinking about this more, of the guys seeing an increase in temperatures, do you know what fluids were used?

 

[max78]

It's not a fluid issue, the 6R80 has a built in thermostat, remove it and it will never see 170 degrees. Not sure why it changed with new fluid, but my guess is its thermostat related.

 

[DieselMonk]

It's not a fluid issue, the 6R80 has a built in thermostat, remove it and it will never see 170 degrees. Not sure why it changed with new fluid, but my guess is its thermostat related.

That is where I put my money on to as well… It’s a known problem in the F150 world. My bet is that the filter and fluid got changed, but nobody did anything with that thermostat inside the 6R80 which restricts the oil flow to the oil cooler. There is a thermostat bypass one can buy.

 

[Linksvu]

It's not a fluid issue, the 6R80 has a built in thermostat, remove it and it will never see 170 degrees. Not sure why it changed with new fluid, but my guess is its thermostat related.

I don’t see this being the reason. The thermostat could be working properly but the fluid could be retaining heat differently, or the system could no longer be dissipating heat the same, or the trans could be building heat more than it used to.

In all of those, the fluid temp could rise with the thermostat working as it should. And that doesn’t explain why the temps would reach highs it didn’t before, with a good working stat. If the stat was only opening later (say 4 degrees), the fluid and cooler should still cool it down to what it was if they are all operating the same.

It seems more likely some combination of fluid quantity (esp since that is difficult to measure) and efficiency in the trans cooling (200k worth of bent fins hindering air flow).