Ahh I see. I'm not super impressed with the factory coolant gauge in the cluster. I've used the OBII scanner to get the actual coolant temps. The factory gauge is fairly accurate until the 210 mark, after that the gauge will only go to the second tick mark after 210 until the PCM reads 254°F and then it goes immediately over to 260°F and the check gauges light comes on. (I had a crap copper radiator that did not perform very well in 115°F up the I-17 hill to Prescott) I mention this because I've seen another post in another thread of a guy who said his jeep would "periodically spike to 260°F" but I am guessing that if he has a 97+ XJ then the gauge isn't telling you much. Obviously a momentary spike of 40 degrees is impossible. The 4.0 isn't a sheet of tin foil!
Now that my rant is over, my only mounting location for the remote transmission cooler has been occupied by the ox locker actuator that I had installed on Thursday. It was above the rear axle. I was driving a 2010 Mercury Mariner the other day and I wondered why the AC was so damn cold at idle while stopped. I got out and I could hear a massive electric fan, but more importantly, I could incredible suction from the front of the grille. When comparing it to my XJ, the difference is very noticeable. Perhaps, as most people say, the XJ just needs a lot of airflow. The engineers obviously wanted to "dumb down" the temperature gauge. Most modern cars I've driven do the same, but the gauge does not move from the center until there is an overheating concern. But considering that any temperature below 254°F is not overheating, this discussion is irrelevant.