I installed a aftermarket radiator in my truck which has the trans cooling ports stacked vertically instead of horizontally on the bottom like the old rad. Anyway on a C-6 which trans line is the outgoing and which one is the return? I understand that the outgoing should attach at the top of the rad and the return at the bottom. Thanks

Dan

 

I used to know, but then again it doesn't really matter as long as the fluid flows thru the cooler.

 

You could do like I did, and just start the truck with the lines detached and watch which one squirts, but it does get messy.

 

It is a straight through connection, but I'd let the input go to the top of the ports - letting gravity assist the flow of ATF. Forcing it in the bottom and then UP to the top would not be a good idea

 

The difference in pressure would be less than 1 psi and the tranny pump will never notice, since the psi in the tranny can be over 125-180 psi.

 

it really does not matter what you pick. it will all flow the same.

 

If you are running your aftermarkert cooler in series wiyh your factory in radiator you want the cooler to be after the radiator one .If you do not do it this way the radiator will put heat back into the fluid.Unhook one factory line start vehicle briefly BRIEFLY!!!!!!!
& see which way fluids goes if from pressure side it will shoot out a foot or so.f shoots from line then you use other line to run to cooler if it shoots from radiator then run to cooler then back to tranny. Up here in the GREAT WHITE NORTH if you do not run through the radiator cooler sometimes tranny will act funny for a mile or 2 in cold weather.this is because the radiator warms up fluid a little if you bypass the radiator cooler up hetre takes a little rollin to get fluid up to temp. Remember every 20 degrees down to 180 degrees doubles tranny life.

 

the front line is out to the cooler the rear line is the return line.

 

cool enough monster pouring here did not want to crawl in mud to see right now