The Derale Hyper-Cool Remote Cooler Assembly w/ Fans, -10 AN Inlets # D15845 will be enough to properly cool the transmission on your 1975 Chevrolet C20 pickup. You can install the Derale Premium In-Line Fan Control Thermostat # D35022 that will turn on your fans when the transmission fluid temperature reaches 180 degrees Fahrenheit. view full answer...
Yes, the Derale 12" High-Output, Electric Radiator Fan # D16925 can be used with a PWM. Derale also makes assemblies with an integrated PWM controller like the # D66820 if you don't already have one. view full answer...
The Flex-a-lite 15" Black Magic Xtreme Electric Radiator Fan with Shroud # FLX180 will come with all the components needed for the installation. You will of course need your own tools to complete the installation if you are doing it yourself. If you would like to be able to switch on the fan from a switch you will also need the Flex-a-lite Illuminated Auxillary Switch # FLX31148 as well. view full answer...