Hey guys, just bought a belt, 7 round trailer plug-in, and a transmission cooler for my 94 f150 long bed 300. Trying to get truck ready for towing. Already installed a 3:73 gear. My question is on plumbing the cooler. My plans were to just use it as a secondary cooler inline with the factory radiator cooler. The guy at the oreillys counter seemed knowledgeable(better than most at the box stores), and he recommended just bypassing the factory cooler and only using this auxiliary one. One thing he said made sense and got me thinking he may have something here, "it eliminates some heat from the radiator, allowing better coolant cool down." What are your alls opinions, and how did you plumb yours up?

 

I don't have an opinion on it, I only have facts garnered from my time as an Automatic Transmission Cooling Engineer at Ford.

I measured temperatures throughout the system. This included ATF temp into and out of the radiator and engine coolant temp inside the radiator next to the transmission cooler. These measurements showed that the ATF going into the radiator was ALWAYS warmer than the coolant around the cooler. Not usually or often, ALWAYS warmer. So it was impossible for the coolant to warm the ATF. It will never happen.

The best thing you can do for your trans is to run to ATF to the radiator, then to the new cooler, then back to the transmission.

 

I kept mine going through the cooler as well for reasons that Mark stated. I did replace my factory cooler with an early model superduty type cooler which is double the size as my OEM piece. I believe the later model (6.0L) coolers are even larger.