Hello
Found this thread, I don´t know if you got the trans cooler installed.
My story, bought a 2013 XLT 3.5 V6 50k miles a couple of months ago, no towing package. Doing a through maintenance noticed transmission fluid was dark brown, freaked out. Found a youtube video saying is kind of "normal" for Mercon LV after as low as 15k miles. Still did 4 successive drain and fill of the trans (used about 4.5 quarts on the fill). Fluid is dark red now, much better. Also started monitoring transmission temps using the Torque app. City stop and go traffic temps would climb to 204 F after just 10 minutes. Just yesterday with highway 65mph driving after 45 min, took a look at the trans temp, 206 F. Just to be clear, the vehicle was full (7 passengers) but no luggage, no mountain climbing, just flat highway 85 F ambient temps. I will be getting a cooler soon. Doing some research about the Hayden coolers, just have to find the correct size. I´m leaning towards the Hayden 1677 Rapid Cool, it´s 11"x7.5". One review about a Volvo said it helped to lower temps down 30 degrees F. I won´t be doing any towing, so this could be the size for me (206 - 30 = 176 which is perfect). Of course, this is just a guess, it´s not the same vehicle. The bigger cooler after this one, one review said it helped lower the tans temp 40 degrees while towing, so it could be too large for my non towing driving.