Transmission Temps While Towing

[Bluesky 07]

Trying to put some recent observations in context. My truck is a 2007 V6 with external transmission cooler controlled by a thermal valve that opens at around 180, and I use OBD Fusion to monitor pan & TC temps.

While towing about 4K pounds in hilly terrain, the pan never went above 190 but I got transient TC temps of 225-230 on steep grades. This never lasted longer than about a minute or so. The pan temp seems to be what controls the thermal valve so it would have to be 180 to 185 before the cooler opened up. Biggest discrepancy I saw between the two was 190 at the pan and 229 at the TC.

This seems like how the cooler system should work and from what I understand, only prolonged temps at these levels are harmful. Still, I wanted to get opinions from people with more knowledge or experience with this stuff.


TIA for any insight.

 

[ArthurKotb]

I have a V8 and tow a 6500 lb. travel trailer. I do not have any OBD device connected. When I tow I don't try to maintain speed if I'm going through hills. I also down shift to make it easier on the power train. If it's a constant up/down terrain (or strong head wind) I stay in 4th. I've never had the A/T Oil Temp light come on.

 

[Drcoffee]

The torque converter is pure fluid friction so temps will be higher there. When you tow, put the shifter in 4th gear which will lock up the TC this will stop the high temps from TC slipping

 

[Bluesky 07]

The torque converter is pure fluid friction so temps will be higher there. When you tow, put the shifter in 4th gear which will lock up the TC this will stop the high temps from TC slipping

I only tow in 4. Should have mentioned that in my post.