Two lines are attached to the cooling tank at the bottom of the radiator. Which is the input line and which is the output line? One attaching neck is toward the driver's side and the other is more toward the passenger side. Both lines run back up to the automatic transmission, but it is harder for me to describe which line while using the trans as a reference. Thanks.

 

Why? Doesn't matter. The cooler doesn't have a check valve in it.

 

I was thinking about running the fluid thru the present cooler at the bottom of the engine radiator, then running it thru a trans fluid radiator-type cooler, which then return by the rubber hose to the automatic trans. Which one should be hooked up between the present cooler and the radiator-type trans fluid cooler?