Bringing this topic up again.... 2025 GMC Sierra 1500 with 3.0 & 10L80. Was seeing temperatures of around 200°F in typical summer conditions. So, installed the PPE thermal bypass. Summer driving in the Midwest with ambient temps around 80°F* seeing only ~130°F transmission temps. So, about 50* delta.
Now that it's winter and the ambient temperature is roughly 30°F, I'm still seeing only a 50°F delta. Meaning, my trans temp is only around 80-90* tops. PPE states that I must remove the bypass each winter and then reinstall it in the spring. Seriously?!?
Question... how cool is too cool?
I'm not worried about the potential 0.1 mpg efficiency gain from a higher-temperature transmission, but I AM concerned that at only 80°F, is the transmission being impacted and doing its job properly? What happens when it's 0* outside?