Tammy20002500

My truck is older ('00 2500), with a mechanical fan. Over the years,I've been debating putting in a 180 deg thermostat mostly just to run it at a lower temp around town. The coolant itself has never exceeded 210, even when towing hard through the desert. The transmission however was another issue. when towing in summer in the desert, AC on etc. the trans would get up near the 200 mark, or a little higher on grades. I wanted to cool the trans down, but I had two additional goals; 1. I did not want the trans to run cooler all the time (when not towing, or in the winter etc) or too cold period. 2. I did not want to add heat to the radiator stack. (putting an additional cooler for oil or trans fluid etc. in front of the radiator does make the target fluid cooler, but at the expense of adding heat to everything behind it). My solution was to add a B&M Hi-Tek trans cooler with a fan and mount it horizontal under the truck. I built a rack from frame to frame just behind the transmission mount cross member and I tapped into the return line for the tranny for the fluid feed. The results were amazing. Just adding the cooler (without its fan on and no air blowing through it since its horizontal under the truck) lowered the trans operating temp by around 20 deg in unladen around town driving. (It now warms up to about 140 on an 80 deg day). Towing is even better. Without the cooler fan running, I'm at about 160 with the AC on and at freeway speed with a 4K lbs trailer on an 90 deg day. For hills, I can flip on the fan, and she'll stay around 160 on a 6% grade. The unintended side effect is that with the trans operating at a lower temp, the trans fluid that is circulating through the radiator core and the factory auxiliary cooler, is much colder, which in turn does not transfer as much heat to the radiator core & oil cooler. The result is that my oil temp has lowered (i have a gauge) and from this, I can extrapolate that I now have some additional cooling capacity for the engine coolant (i don't know for sure because of the 210 thermostat.) but it makes sense. Also, without having as much heat being fed to the engine bay, she seems to have picked up some horses when towing. (i know, its probably my imagination) just a thought on skinning the the same cat a different way.