Temp needed for Torque Converter lock up

[Ian Gross]

So Ive been getting horrendous gas mileage and im going to attribute it to the fact that my transmission is running too cold. I have really started to notice this since the weather is so cold now in the northeast. Im currently running at 149ish degrees. Im thinking that the Aux cooler i installed in series with the factory cooler is just too much cooling and in fact hurting instead of helping.



So My question is What temperature is needed the in the tranny to get the converter to lock up?



Thanks Ian

 

[EddieS'04]

I think the lock up is done from the computer at vehicle speed. You could block off the aux cooler and see what happens. shouldnt hurt anything as long as the factory cooler is still in service.

 

[Scott Tanner]

is the aux cooler before or after the radiator? a simple move may fix, as the rad cooler will warm it back up if too cool

 

[Dreman]

Block it with a piece of cardboard wrapped around it to see if that helps. You just need to stop the airflow. I don't have any idea if it will fix the torque converter problem, though.

 

[Todd Z]

My tranny runs at 125, Never an issue...... The converter locks based on engine temp, Not tranny temp....and I think it is somewhere around 65 degrees.... What is your engine running at ???



If you go over 45MPH and the engine rpms drop another 500 RPM or so, that is the converter locking up...



Todd Z

 

[Ian Gross]

Hmm ... Well I do experience the 500rpm drop on the highway soooo I guess my first thought was wrong here. I dont have a water temp gauge but while driving on the highway at 65ish the factory gauge is right in the middle of the range.



I havent done anything different on the truck to cause the gas mileage in the gutter, other than the aux cooler.... So I think I'm going to bypass the aux cooler and see what that gets me for a tank or two.



Thanks for the quick help guys.



Ian

 

[Todd Z]

Worth a try...

Keep us posted..



Todd Z

 

[Dreman]

Have the stations in your area switched to winter gas? It's never been a problem around my neck of the woods, but I understand it can kill gas mileage in those areas that have to have a winter gas formulation.

 

[Chris Taylor]

Once mine finally warms up with my tranny cooler, it's about 125 in the winter(just like Todds). Even at 90 degrees(tranny temp), the torque coverter locks up about 45 mph.



I think dreman might be right about the winter gas. I drop 2-3 mpg when using it, and gain that much in the spring. Around here, winter gas has 10% ethanol in it to keep the fuel line from freezing up, and that ethanol just kills the milage.

 

[EddieS'04]

We have 10% ethanol year round in houston area..

 

[shawn stonbraker 2]

Same here with the MPG drop at winter.