Mike L. stated it correctly when he said there is no or little air flow that goes through the transmission cooler at speeds below 35-40 mph. I can pull our fifth wheel up steep grades and usually hold 50 mph and in general there is not an overheating problem with the transmission. But, I can be driving in a city, not towing anything and see the transmission temperature up to 200+ degrees. A Mike L. cooler makes sense in the overall picture to lower the temperature a small amount, but it still makes more sense that a cooling fan is needed at low or no speeds. Stop and go traffic is equal to high temperatures in the transmission because of too low of air flow through the cooler.
Question...Has anyone figured out how to put a cooling fan with a switch of some sort on the front of the transmission cooler so the fan could be turned on when the transmission temp goes too high? If you have done this, please give details. Thanks! Ted

I'm working on puting a 10" fan on "Duramaxdiesel" Nick's truck. I installed a 12" by 12" tru-cool & it works great but at the track theres no air flow to coll the drag runs off. So I'm going to run it off a S/W over relay to cool it off at the track. I'll post how it works out.
Tom

Tom,

Results, pictures, and part numbers would be great!

Ted

I am testing a fan for my cooler at present. I have chosen a smaller fan with higher CFM because of air blockage that results from mounting the fan in front of the cooler. I will have a report in a few weeks.
mike

Mike, i will take 1 as soon as they are ready.

Mike L.

Please keep us informed. The combination of a bigger cooler and a fan would probably solve my hi temperature problem and many others that are having the same problem.

Ted