The 6R80 Transmission has an internal Thermal Bypass that operates much like the thermostat in your cooling system Upon start up, the bypass is closed limiting fluid flow through the on board auxiliary transmission fluid coolers to help get the transmission up to temperature. Once it reaches its optimal temp, the valve opens allowing fluid to enter the transmission after passing through the designated cooler. This valve is found on all 2011-14 F150 and Mustang 6R80 transmissions. All 2015-17 Mustang Transmissions also have it, but 15-17 F150 transmissions do not. The 15-17 F150 has an external bypass cooler unit controlling the flow. For those using a Gen 2 F150 transmission in a Coyote Swap or any other swap, installation of this valve is important to ensure the transmission continues to work as intended. This is because the external unit is typically not used in the swap. This is also important to anyone using a Gen 2 6r80 core for high performance transmission swaps.
