Automatic transmission fluid turns into a pink milky consistency, like a strawberry milkshake, when it mixes with coolant in the radiator well. The transmission's cooler is located in the coolest radiator well after the coolant has flowed through the cooling fins. When a leak forms in this cooler, the two liquids mix, resulting in foamy pink transmission fluid. The engine's coolant now has transmission fluid mixed in. It can be seen swirling around in the radiator neck. A flush will be required to remove these cross-contaminated fluids.