vehicles with trans temp readout

wintersun wrote:
The GM trucks all do this but it is less helpful than you might expect. My trans fluid reads about 60 degrees hotter than the ambient air temp. If it is 60 degrees outside the fluid will run at 110-120 degrees. When it was 113 on a trip last month the fluid temp go up to 178 degrees. I am not going to drive it any differently regardless and the same applies to the tire temps. When cold the front will be at 65 and rear at 80 PSI. When they are hot they pressure goes up 8-10 PSI but so what?

What truck to you have? I have found that the trans temps in my last 2 GMs ('06 Duramax/Allison and '10 1500 Suburban) level out somewhat regardless of conditions or temps -- they don't seem tied to ambient like others always mention. Driving unloaded, it seems that temps will be between 140 and 160* once everything is warmed up, regardless of ambient temp. For example, I drove for 12 hours on the interstate in temps between -15* and +5* last winter, and my trans temps stayed in the range of 145-155* the whole trip; I drove 8 hrs on the interstate in ambient temps around 105* this summer, and my trans temps hovered between 160 and 170*.

Towing, I seem to level out around 200* all the time on flat ground, again whether it is 50* or 100* outside. Stop and go traffic will push temps up to 210*, and hills will make it top out around 225*, but it comes right back down to 200* when the hill is done.