How to Determine Transmission Return Line for Installing Cooler on Ford F-150

Updated 01/28/2019 | Published 01/26/2019

Question:

On my ford f150 with a 4r70w Transmission the cooler has two lInes upper and lower and on the transmission it has a upper and lower hose inlet which one hooks to which.

asked by: Rodney

Expert Reply:

The best way to determine which line on a transmission cooler is the return line from the radiator is to use the following procedure:

1. Start engine while engine is cold
2. Place transmission shift lever in drive for no more than 10 seconds
3. Place in Park, stop engine, and remove keys
4. Identify the oil return line by feeling both oil lines. The coolest line is the oil return line.

On the aftermarket transmission cooler the ports are not input specific or output specific. It is not directional so you can choose either port for either function. You will want to choose the inlet or outlet port location by what will make your installation easiest.

I tried looking up your vehicle specifically but got conflicting info especially since I am not sure what year your Ford F-150 is.

expert reply by: Jameson C