bad_idea

I recently installed a B&M transmission cooler on my 90 XJ. It worked out easier to route the supply line from the trans to the B&M cooler then radiator cooler then return to transmission. I know it is good practice to keep the radiator cooler in use as it should keep the fluid warm during cold weather. I do not understand why the external cooler should be after the radiator cooler. It seems to me each cooler will do what it is suppose to do no matter the order. The external cooler will shed excessive heat, the radiator cooler will warm the fluid up. What does it matter which happens first? Not trying to start an argument, trying to understand the theory here.

EZEARL

I wondered the same thing before installing my B&M cooler. Found a good explanation at that time here.
https://www.etrailer.com/question-40598.html

bad_idea

I read the article you posted. I can see the logic, but I don't buy it. The cooler in the radiator add a set amount of heat, the external cooler will remove a set amount of heat. Lemme throw out a overly simplified example of my reasoning.

If there are three people standing around with M&Ms. Bill has 50 M&Ms, Steve eats 25 M&Ms, Roger adds 10 M&Ms. It doesn't matter what order it happens, there will be 35 M&MS left in the end.

From a practical application standpoint, my cooler has been installed before the radiator cooler for a week now and have put 200 miles on the Jeep of mixed driving, some stop and go. Transmission temperature has not exceeded 160, hanging around 125 most of the time. I'll continue to run it this way until I have overheating issues.