As the majority of us know the AW4 runs hotter under normal circumstances, more so during hot weather and hard driving for whatever reason.

I am currently looking into adding an auxiliary cooler, but before I can do that I need to clear up some information about the stock setup that I've found. I've run into an issue of contradictory information regarding the coolant lines for the transmission and the radiator.

In the information that I gathered I found that the rear coolant port on the tranny is the return line, and that it should be coming from the top port on the radiator to this port.

With my jeep this is not the case. The rear line runs from the bottom port on the radiator.

I will be attaching photos to this so that you may see for yourselves. Would someone please clarify to as to what I am seeing wrong or if I just found bad information?

 

The important part to remember is that the rear tranny line on the AW4 is always the return line (easy way to remember is "r" for rear = return).

Depending on how your XJ was originally optioned out it may have the line going to either the top or the bottom of the radiator. Don't overthink it. Follow the instructions from the manufacturer of the aux cooler you're going to install but just be certain the return line goes to the rear of the AW4.

 

What he said. Don't sweat the radiator connections - it's really not critical that they go in a particular direction. Rear is return, and that IS critical.

Plumb your cooler in accordingly.