Trans Fluid Leaking Into Radiator Coolant

I have a 2004 Venture with 3.4l engine. Last month trans fluid and coolant overflow at normal level. Today, trans starting growling. Checked and trans fluid was two quarts low (despite no leaks on driveway). After added trans fluid and driving for 5 minutes re-checked under hood and noticed coolant overflow was overflowing onto the ground - it was full of trans fluid and coolant. I don't see any leaks or problems but it sounds like a leak in the trans cooler at the radiator. Anyone else ever have this problem? Is the trans cooler part of the radiator or can it be replaced by itself? If I have to replace the entire radiator is it a big deal? I only saw one other thread about replacing the radiator. Thanks for the input!

HELLO,IT SOUNDS LIKE U ARE RIGHT.the rad cooler can be replaced but not a DIY should be a rad repair shop job.its not hard to replace rad.all coolant hoses need replacing & a couple of good coolant flushes.Good Luck!!