feets

I bought my '92 D250 used 13 years ago. There is a large transmission cooler under the driver's front corner of the bed. It lays horizontally with stone shields on each end. There's an electric fan mounted on top that is thermostatically controlled. I heard it kick in for the first time ever a month ago when I got the truck stuck off road.

Are these things common or is it simply an aftermarket setup installed by the previous owner? I don't see any reference to it in my shop manual.

Firstgenfanatic

It sounds like you have the original "dealership installed" auxilary underbed cooler. These are great units to have. The only goofy part about them is the temp sensor in them. The temp sensor is set to a fairly high temperature for the electric fan to turn on. I prefer to have a manual toggle switch ran to the electric fan.

jeepsuck

what is that temperature? i have never heard mine work, coincidentally my transmission recently took a dump on me. been wondering about a way to test the thermostatic switch and make sure its working.