I am install my Trans cooler this weekend, Anyone know which is better for Automatic Transmission. I heard good things about both, But which is better. Royal Purple or Redline.

 

I would personally use the Redline just b/c its what majority of people i know use for racing. It also works great for street. Your trans will run cooler and it provides more protection. It is also synthetic. I've heard of Royal Purple, just no experience with it.