Hey Powerluvr. I just picked up my rebuilt, beefed up C6 tranny from my rebuilder. I asked him the same question, and he told me to forget the cooler in the radiator and just use the biggest stand alone cooler I can find. So, that's what I will do. Summit racing and Jegs have a bunch of them. Also, he said just make sure that it gets adequate air flow. I've read other posts on this forum and others, and you always get the "never bypass the radiator", or "you don't need to bypass the radiator." Anyway, considering this guy has been in the tranny business for 42 years, needless to say, I will do what he told me to do. Hope this helps