I have a 2014 STX Sport SCrew and I recently added a Circle D 2B converter. Trans temps get up between 200 and 205. I have the factory auxiliary cooler but I want to replace it with a Tru Cool Max. The Tru Cool Max says not to use on trucks with 1/2" cooler lines but I know some people run this cooler on 09-14 F150's. Has Ford changed the cooler line size or are people running this cooler anyway without issue? Any help appreciated. I have not been able to find a comparable cooler with 1/2" connections.

 

200 to 205 is normal for a 6R80. Flow to the cooler is thermostatically controlled.

 

Why is it that you want a larger cooler? 195-205 is normal unloaded operating temp. As glc stated there is a thermostat in line with the cooler. It's actually located on the valve body of the transmission. It is actually more harmful to have colder oil than warmer oil. I would re consider the idea of a larger cooler. I've hauled 1700lbs up a 6% grade with steady throttle @5000 elevation and only saw 218. The grand does cool off rapidly on a slight descent or straight road FYI.

 

I feel the trans would live longer if it stayed in the 165-185 range. I found a 6R80 manual online and it did state that 193-215 was normal operating range. We all know that the higher stall converter will raise the temp. A friend of mine has the exact same truck except for color and rear axle ratio. We bought them 2 weeks apart from the same dealer and same price. I have logged both trucks and my trans runs 25 degrees hotter than his in the same conditions. No major concern, but dropping the temps back down to where his are would be beneficial. However, I probably will not change the cooler since I cannot use the cooler I want and due to the thermostatic control of fluid to the cooler.

 

His driving distance/characteristics may be different than yours. I've clocked my truck temps in the a.m. On my 19 mile drive to work where trains gets up to 170. Then in the evening when it is a little warmer it gets to 190 ish. The oil is designed to operate above 200*
Flashpoint of oil is 365* so as long as you are below that I'm sure your fine! Lol

 

I logged both trucks. First mine, then his, the same exact route and driving, back to back so I could get as accurate of comparison as possible.

 

He actually could have a faulty thermostat....

 

Go ahead and try that if you think you've done more research and development on this trans than the engineers at ZF who designed it and the Ford engineers who speced it out and designed the installation parameters. What on earth were they thinking using Mercron V fluid in there anyway when just slapping on some big *** cooler would be better?!?

 

 

The 6R80 doesn't take Mercon V - it takes Mercon LV.

 

If I'm reading this right, the difference between your trucks is that yours has a higher stall converter. Both should heat up to the thermostat temperature, but obviously the higher stall unit will get up there quicker. Try 30 minutes of heavy stop and go (0-30mph) driving in the same conditions on both trucks and you should see both reach similar temperatures if the cooler is sufficiently sized..

I'd suggest once you reach 220 trans fluid temperature, it's time for a larger cooler. I'm also not sure how you're measuring the temperature, but accurate probes aren't cheap. Who knows how accurate the built-in sensors are, especially on two different trucks that came off an assembly line.

I also like to see <170F temperatures in general auto transmission use. I have no idea why the production specifications were made, but wouldn't be surprised if lower temperatures were still beneficial. Many decisions made for production vehicles are controlled by people other than the engineers, and they have no problem requiring <30k fluid flushes when many fluids can actually go 100k+ if it isn't allowed to reach higher operating temperatures.