I`m installing a cooler for my trans. The directions say to start the motor and put it in drive for 10 seconds. Then feel both lines going to the rad. The cooler is the return line. Mine felt the same temperature. Does anyone know if the return is the top or bottom line? This is on my `86 camero. Thanks!

 

Usually the bottom one on the radiator is the return line. How about you take one off n see if it spits out or sucks in? With car running.

 

I`ll take the bottom off and check it. Thanks for the quick help.

 

It's best to take it off with the car not running, then unhook your distributor wire (so she won't fire up) and just turn it over a few times. It'll spit enough to tell which way the fluid flows.