I'm now an owner of a 2012 Suburban LS and want to add a external tranny cooler. It has the internal radiator cooler and I've been told that the hot line enters the internal cooler at the bottom and exits back to the tranny from the top line. Is that correct? I want to put the external cooler after the internal and need to be certain which line to connect to, top or bottom. Thanks for your help, I'm new to the Chevrolet line of vehicles and looking forward to learning much from the forum.

 

Welcome from Florida. This is a simple way to check which line is from the tranny. Hope it helps you.

https://www.etrailer.com/question-105876.html

 

Thanks for the link, I've often tried to find info on etrailers but not had much success. I did try that and it confirms that the fluid enters the internal cooler at the bottom and exits from the top line. Got the cooler installed today with no leaks and everything put back together and working fine.