Transmission Fluid Temperature

[Colt45ws]

Originally Posted By: supton
Something I'd watch out for, is that if the temperature shown does not change "fast" then it might be pan temperature. Meaning the oil will see much higher temps coming out of the convertor. 180 in the pan might be 250 (momentary!) before headed to the convertor.


Yeah, my numbers are based on transmission sump temperature. That gives you ~50F of buffer for a unlocked converter pulling up a hill or whatever.
210-250, 250-270, 300+ would be ranges I would expect on the cooler out line for the same ranges I posted earlier.

And I think you meant headed from the converter to the cooler.

 

[meep]

we tend to focus on the AT, which is an actively cooled system. We tend to overlook the passively cooled diff, which according to some of the OTR studies I've read, is really the area to pay attention to if you're towing heavy. I've come off of mountain passes with more heat coming from the axle than the hood. Easily way too hot to touch, easily above engine temp.

 

[clinebarger]

Originally Posted By: Colt45ws
Originally Posted By: supton
Something I'd watch out for, is that if the temperature shown does not change "fast" then it might be pan temperature. Meaning the oil will see much higher temps coming out of the convertor. 180 in the pan might be 250 (momentary!) before headed to the convertor.


Yeah, my numbers are based on transmission sump temperature. That gives you ~50F of buffer for a unlocked converter pulling up a hill or whatever.
210-250, 250-270, 300+ would be ranges I would expect on the cooler out line for the same ranges I posted earlier.

And I think you meant headed from the converter to the cooler.



I have measured/data-logged a little over 400 degree converter outlet temperatures on a radical street/strip truck with a 4000 RPM stall because the Dumba** gets on the Trans Brake soon as he stages. We keep it cool though with a HUGE Setrab cooler with dual Spal 10" fans mounted in the bed.

 

[Fasttimez]

My new F150 with 6R80 Trans & Mercon LV says normal operating temp is 205-215. The thermostatic bypass doesn't even open to circulate fluid through the cooler until fluid temps reach 190. It says the truck will go into limp mode ONLY if it sees trans temps of 270 for 5 consecutive seconds or longer.

 

[SilverFusion2010]

Originally Posted By: meep
we tend to focus on the AT, which is an actively cooled system. We tend to overlook the passively cooled diff, which according to some of the OTR studies I've read, is really the area to pay attention to if you're towing heavy. I've come off of mountain passes with more heat coming from the axle than the hood. Easily way too hot to touch, easily above engine temp.


Thicker oil? Cooling fins? A midget to blow on it?

 

[zeng]

Thicker oil would help.
If as-is oil grade is 75W85/90, goes up 2 grades to xW110.
Or from 80W90 to xW140.