Brakes, transmission too hot?

[LariatRVer]

Good morning,

Questions first (BLUF)-The transmission gauge on our truck reports as a graph, not with numbers. Many have said they watch the transmission temperature to not exceed “x” degrees. Any thoughts on how far past 50% on the gauge is danger zone and I should pull over and let it cool down? It is almost always around 45% pulling through hot, hot Texas.

Second question, using an IR thermometer to check brake temperature on a down hill run, some have reported 200 degrees as “not to worry.” Any opinions on what is the “to worry” temperature?

Background, We are long time flatlanders heading for Utah via Colorado with a 2020 F150 SCREW 3.5 SB Max Tow, pulling an approximate 6500# travel trailer.

Thanks in advance.

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[imnuts]

Depending on what model you have, you can enable the transmission temp under the gauge on the cluster/IPC. Sitting at ~50% is normal operating temperature. I don't know what temp it will start to increase though. I'd say if you see it somewhere in the ⅔-¾ range you should try to ease up to cool things off.

Only way I know to tell if the brakes are overheating is if you start to experience brake fade.

 

[powerboatr]

you can enable temps on the trans temp and engine coolant with forscan
oil temp is a no go unless you have the raptor.
on my super duty you were able to see all .
data logging in forscan you can see oil temps but for some reason it will not show up on dash unless you have the raptor
my trans runs 194 to 212 easy empty at 70 mph with OAT of 100 . last week on way to tyler it was 105 outside and it ran 209 on highway then peaked a bit in traffic then dropped to 199 to 204
seems hot for me, but it seems to like those temps
engine ran 199 to 208 same run.
this wa with ac on 5 fan speed and temps set at 66 or less

 

[LariatRVer]

Forscan, excellent. We dealt with that when we added LED lights. Thanks

 

[hotrodmex]

my trans runs 194 to 212 easy empty at 70 mph with OAT of 100 . last week on way to tyler it was 105 outside and it ran 209 on highway then peaked a bit in traffic then dropped to 199 to 204
seems hot for me, but it seems to like those temps

The 10R80 has a normal operating temp range of 200 to 215, I believe. It's at least as high as the 20_ range.

I haven't seen any hard number, but the anecdotal data suggest that 230 is the temp you need to start paying attention (yellow on the gauge), and 250 should command your attention.

 

[LariatRVer]

Numbers, love me some numbers! I will watch the trend as we go forward. I also have read anecdotal accounts of the truck going in to a limp mode if it “senses danger”. Although I may be mixing that up with Powerboost things.

 

[Oxford_Powerboost]

Numbers, love me some numbers! I will watch the trend as we go forward. I also have read anecdotal accounts of the truck going in to a limp mode if it “senses danger”. Although I may be mixing that up with Powerboost things.

You’re correct about that - more numbers for you but coolant, idk them for trans. At 235 coolant temp, even without forscan you’ll get the digital coolant temp on the dash. At 245, the truck will give you a warning that engine power is reduced to lower coolant temp. Usually it wouldn’t go past this, but I imagine it’s not too much hotter where you’ll be told to pull over to allow engine to cool

haven’t seen issues out of this trans really, but it should have the same progressions for trans getting hot. For what it’s worth - I have forscan temps enabled And the highest trans temp I’ve seen was 223. No warnings at that point and the gauge had not moved

 

[powerboatr]

You’re correct about that - more numbers for you but coolant, idk them for trans. At 235 coolant temp, even without forscan you’ll get the digital coolant temp on the dash. At 245, the truck will give you a warning that engine power is reduced to lower coolant temp. Usually it wouldn’t go past this, but I imagine it’s not too much hotter where you’ll be told to pull over to allow engine to cool

haven’t seen issues out of this trans really, but it should have the same progressions for trans getting hot. For what it’s worth - I have forscan temps enabled And the highest trans temp I’ve seen was 223. No warnings at that point and the gauge had not moved

i have sat idling in park for over 30 minutes in 105 F degree heat with ac on 66 and 5 fan speed, pointed into the sun.
it hovered back in forth between 192 to 196 on water temps. and trans stayed right at 199 the whole time
i did bump idle up to 1k a few times with my foot and the water would drop back to 192 .

fans screaming outside
momentarily jumped to 200 when i started driving again, then settled back to why perceive as normal for this engine. my psd 250 ran 187 on water so its a learning curve

 

[Oxford_Powerboost]

i have sat idling in park for over 30 minutes in 105 F degree heat with ac on 66 and 5 fan speed, pointed into the sun.
it hovered back in forth between 192 to 196 on water temps. and trans stayed right at 199 the whole time
i did bump idle up to 1k a few times with my foot and the water would drop back to 192 .

fans screaming outside
momentarily jumped to 200 when i started driving again, then settled back to why perceive as normal for this engine. my psd 250 ran 187 on water so its a learning curve

I think some of it depends on the motor too. My 3.5 wouldn’t mind 192 at all. In fact, without A/C on I don’t even think the engine fan would come on. Idk if a 5.0 or 2.7 runs differently though.
All our trans are pretty much the same though, so those numbers should be comparable. Usually in unloaded daily driving my trans runs 200-205. Occasionally it Will creep its way up to 212 in a lot of stop and go. I think that’s within spec for the 10R80

 

[Calson]

The flash point for ATF is 350 degrees. When ATF temp gauges started to appear many people freaked out at seeing a temperature greater than 200 degrees.

I would worry about brakes that do not get hot as it would mean they are not doing their job of changing kinetic energy into heat energy.

With a trailer what is important is to have the brake controller working properly so that the trailer brakes are doing their share of the braking.

 

[imnuts]

I tried to find the specs for the brake fluid, but they are scarce it seems for DOT4 fluid after a quick search. If you can find the boiling point of the brake fluid, keep brake temps under it.

 

[hotrodmex]

I tried to find the specs for the brake fluid, but they are scarce it seems for DOT4 fluid after a quick search. If you can find the boiling point of the brake fluid, keep brake temps under it.

DOT 4 is about mid 400s dry, low 300s wet. You go by the wet unless you just bled the system, since it starts moving to that number the instant you pour it.

You can go over those temps, hitting 800f if needed, for short bursts due to cooling, the thermal mass between the friction surface and the brake fluid, and the thermal transfer of the brake fluid itself. If you're at that temp for a while, that's when you risk of fluid boiling.

One of my reach projects will be brake ducting for the front. Hopefully the pad selection improves as well.

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