I just opened the hood of my Lancer 08 (Automatic) this morning to see the oil levels and coolant and when i opened the Coolant bottle i noticed it was full of a yellowish tough fluid, i opened the radiator cap and it started expulsing that same fluid and when i checked my transmission fluid level it was empty. It mixed up both fluids. My cousin told me that there is a hose that gives coolant to the transmission to keep it cool but i dont know if it's that or should i buy a new radiator. Anyone can help?

 

Your cousin is correct. There is an internal transmission cooler inside the radiator. A leak developed internally and started to mix the two fluids together.

Time for a radiator replacement before more damage occurs. You should also flush both the transmission fluid, and engine coolant completely.