I do not have the tow package .. One time I was towing a bunch of crap .. and driving fast in overdrive and my transmission started spaying out fluid from the rubber seal on the pan.. it was spraying all of the exhaust and smoking like crazy ..
So I decided I needed a trans cooler.
Stock.. your trans oil goes to the radiator, is cooled, then returns to the transmission.
When you hook up the trans cooler, you basically cut the return line and put in cooler inline there.
So the new flow of fluid is from the transmission, to the radiator, to the cooler and then back to the transmission.
Because my radiator was damaged, I just bypassed the radiator all together and went strait to the trans cooler and decided to run two trans coolers... so that's where I ended up.
Here is a pic of how you would normal hook it up ... but like I said .. I did a bypass instead.
[ ]||||||[ ] ... http://www.jeepforum.com/forum/f11/98-green-xj-daily-driver-build-996260/