Cooler, Transmission Oil: Operation
WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
Transmission oil is routed through the cooler where heat is removed from the transmission oil before returning to the transmission. The transmission oil cooler bypass valve aids in achieving desired transmission oil operating temperature, it does this by recirculating the oil back to the transmission without flowing through the transmission oil cooler at low oil temperatures.