Gene, you always give me more to think about, even before I'm cutting my Dakota up. Never thought of making sure the trans fluid also heats up enough to work in cold weather.

How about a thermal bypass valve? When the trans is cold, the bypass valve will divert flow out of the trans right back into the trans. Then once the fluid hits a preset temp, the bypass valve opens and allows flow into the cooler as needed to not exceed the max temp set by the thermal sensor. Once fully hot the bypass valve is fully open and the temp sensor adjusts the bypass valve closed to direct just enough flow through the cooler to maintain an operating temperature range.