which transmission line is the inlet and which one is the return on 2003 Dodge Durango

i am installing a cooler on a 2003 durango(4.7). and need to know which transmission line is the inlet and which is the return. i noticed one is located higher on the transmission than the other.

Asked by for the 2003 Dodge Durango
Generally the higher line on the radiator has fluid going INTO the transmission and the lower one goes back to the transmission, so the higher line has fluid coming out of it and the lower line sucks it back into the transmission. This is because the radiator works by taking in hot coolant from the top and as it goes down through the core it gets cooled by the air going over the tubes.
However, I would verify this by disconnecting the upper transmission cooling line at the radiator and putting it into a bucket. Then have some one start the engine and let it idle for 10-20 seconds, you should see the fluid being pumped in to the bucket.
thanks for the info on the durango transmission lines. i finally got around to installing my cooler and your info. was a big help. thanks again
1 more answer
gravity plays a big factor, it will go the path of least resistance. resistance not allowing for sufficient cooling. the lower is the return, it wouldn't hurt installing an inline filter if its goins to be used for hauling.