Mishimoto Mopar Pentastar / Hemi Thermal Bypass Valve Upgrade

The transmission in your Jeep Wrangler is the heart of its drivetrain. Whether you're hauling groceries or hitting the trail, it's vital to keep it performing at its best, and keeping the transmission fluid cool is crucial to that goal. In an attempt to balance drivability and the health of your transmission, Jeep fitted a thermostatic bypass valve to the lines that feed the transmission cooler. This valve ensures fluid doesn't flow through the cooler before the transmission reaches operating temperature, preventing overcooling in cold environments. However, when the thermostat in this valve fails, it's almost a guarantee your transmission will overheat. Moreover, those who live in hot climates will likely never have to worry about overcooling, rendering the valve a useless flow restriction. That's why Mishimoto has developed a full-flow thermostatic bypass valve for the 2012-2018 Jeep Wrangler. The Mishimoto thermal bypass valve kit includes an all-aluminum CNC-machined housing