I have a 2007 Lariat Screw. In the cooler lines leading to and from the tranny cooler sits a small aluminum box. It is about the size of a deck of cards and sits near the front of the tranny on the pasenger side. It has a circular piece in the bottom that looks like it might spin out. I have no idea what this is, can anyone help? I am going to put in a pic in case my word power is not enough to pique your imaginations.

 

Pic?

 

It's there now.

 

That would be the thermostatic cooler bypass. Basically, your tranny fluid always flows through the radiator cooler, but it won't flow through the external cooler until the trans fluid reaches operating temperature. When the trans fluid is cold, it's not running through that external cooler. So, it's basically like a thermostat for your external tranny cooler.

 

And I thought they were paying me to just do nothing. Thanks for the info "JD".

 

I always wondered about the external tranny coolers. Did the older cars/trucks have this? No need to cool the tranny fluid in 20 degree weather going 60 mph not towing anything.

 

No problem - At least you are getting paid to do nothing! I work strictly on comission - when I'm not doing anything I'm not making anything!!

 

Thermostatic bypass valve. It is set to open at 185*F. Below that the cooling is handled by the radiator loop.