Auto Transmission Temps

[othomas]

I just installed a temp gage on my automatic transmission. While towing my fifth-wheel up a steep grade the temp reached 250 degrees. I was wondering if this a normal temp to see or is this excessive? Thanks in advance for any input.

 

[John]

??????????

Where is the auto. trans. temp sensor mounted? If it was in the trans. pan 250 degrees F. is too high... if it is in the output trans. cooler line you are still OK with 250 degrees F.

 

[othomas]

John;

I have the temp sensor mounted in the transmission output line.

 

[John]

Good!

Bill K (of DTT) told me that (if I remember correctly ) the max. temp. when the sensor is placed in the hot output line should be no more than 280 degrees F.



..... that's why I set my SPA over temp. warning light to 270 degrees.



..... however, with my DTT 93% TC and my driving style I have only recorded a high of 190 degrees F.



..... so, the moral of the story is. . higher TC efficiency (when in fluid coupling) = lower trans. temps.

 

[Fireman Dave]

I just got home from a big towing trip. I was at 150 degrees as long as I stayed locked-up in 3rd. I did see 250 a few times when stuck behind slow traffic on a big grade or when in city traffic on a hot day. See the thread below for more info on my experience.



https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=19880

 

[DieselDoghouse]

Trans temps

I regularly see 190 degrees running solo in stop-n-go when ambient is in the 90's—but it should drop off pretty quick when you're rolling again (140-150). From what I understand the first thing to go with heat (and thus decomposing ATF) are the friction faces of the servos: the clutch packs and the bands. I've though about adding an auxiliary fan for the AT coils since the OEM cooler sits kinda out of the main airstream. Food for thought…