How hot is too hot

BenK wrote:
So similar to questions of which gear to select on an *AUTOMATIC* transmission...it is an AUTOMATIC and let it do it's job...or next vehicle get a manual tranny.. :B

This is not particularly great advice. If your TV is struggling to help slow down your speed when on a long downgrade, then it just might need to be shifted manually into a lower gear than the automatic tranny thinks it needs. There is a good reason why so many trucks with auto transmissions have a manual mode. It's not something that I use regularly, but when it's needed, I'm glad it's there. The rest of the time when towing, I'm glad to just be able to put the transmission in "Drive" and "Tow/Haul".

Coolant temps of 215 are a non-issue.

ATF temps monitoring is more complicated.

Some OEM's have multiple ATF temp sensors and you often do not know where any given value is coming from. It is exiting the cooler? The trans? The sump? Or is it inline somewhere?

All ATF today is at least a synthetic blend, some are full and pretty high end oil. Temps can for over 240-260 where charts show danger, but thats not reality.

But lets say 240-260 ATF temp is found exiting the trans where it would see its peak temp. Consider how long its at that temp before being cooled down again. Is the time even measurable? A couple seconds are best?

So it really matters where that ATF temp reading is coming from.


Aftermarket ATF cooler manufacturers state to monitor ATF temp EXITING THE COOLER. So, if you see 175-200 coming out of the cooler...that would indicated trouble or you need a much larger cooler!!!

So similar to questions of which gear to select on an *AUTOMATIC* transmission...it is an AUTOMATIC and let it do it's job...or next vehicle get a manual tranny.. :B

Unless you have modified your engine, computer(s) and cooling system,

just leave it to the automatic stuff to manage

...or if you are over the OEM's ratings (this is one area that does display where you are in reference to the OEM ratings)...or haven't maintained the vehicle well...

Depends on what era...even brand of TV

Key for performance is when does the computer(s) decide to leave normal power settings and go into 'limp mode' and there are several levels to that

ON the performance side, 'power mode' is also dependent on temperatures (not just one, but several spots it senses and sends info back to the computers). One of those sensors will be the knock sensor...

hasheel wrote:
First trip with the new Rpod. Towing with 2007 Chevy Colorado. 3.7 LTR 5 cyl. have a scan gauge. It would not show trans temp. It does show coolant temp. The coolant temp stayed around 209,211. As it got hilly, and later in the day, the temp rose to 215.
Is this too hot? Doo I need additional cooling? Or a tranny cooler?

happycamper002,

I don't know how it works. There are various codes to enter based on the make and model of the RV. I'm too dense to follow the directions at the scan gauge site, unfortunately.

pianotuna wrote:
Hi,

It is possible to enter codes into the scan gauge which will allow it to read the transmission temperature.

Interesting!

Does it need to have an independent sensing device or you tap into the oil pathway to the main cooling (Radiator) system to get this information?

I don't tow anything but curios nevertheless.

I noticed during my trip to a nearby lake that when going through steep grades, my cooling fan kicks in often like getting extra shot of adrenaline.

I have a full range of gauges on my truck, My rule of thumb is when you see 250 on any fliud guage it is time to try something different.



I have seen 280* on trans temps and when I changed the fluid it smelled burnt.


I have seen 280* on coolant and things were getting tense.

pianotuna wrote:

It is possible to enter codes into the scan gauge which will allow it to read the transmission temperature.

Not every vehicle, especially if it is 10 years old.

A lot of newer trucks have slightly higher thermostats than folks are used to. 215 on a hill is very normal. My ram 3500 tranny stays between 120-150 but I have had other diesels that would get into the 210-240 temps when loaded over 25k lbs. Gauges are your friend.

215 for coolant isn't too hot and may not even trigger the cooling fan.
If it gets above about 226 or so the cooling system is loosing ground and you should stop and let it cool.

Hi,

It is possible to enter codes into the scan gauge which will allow it to read the transmission temperature.