How to Determine the Transmission Cooler Return Lin on a 1999 For F-150

Updated 02/08/2012 | Published 02/05/2012

Question:

I have a 99 f150 I want to know how to put the return lines correctly if so I would like to know which is which for instance where does the hole on top of the transmission goes on the radiator and where does the bottom hole on the transmission goes? Thank you

asked by: Cesar

Expert Reply:

The easiest way to determine the return line on your 1999 Ford F-150 transmission is to start the truck, shift into drive but do not go anywhere. After about 15 seconds or so put the truck back in park and apply the emergency brake. Turn off the truck. Out of the 2 hoses attached to the transmission, one should be warmer than the other. The one that is cooler is the return line. It may sound a little too easy but it works.

expert reply by: Michael H