So, I am going on a camping trip this coming march, and I plan on doing some towing with my XJ. I will be towing my four wheeler (est. 600lbs.) on a 4x6 trailer (est. 400lbs). I also estimate that I will have roughly 300lbs of cargo load inside the Jeep, along with me and my cousin @ 200lbs a piece. Adding this all up I'm thinking the total load I will be putting on my Jeep is about 700lbs inside and 1000lbs towing. The trip I am making is about 250 miles one way, mostly interstate. Although I am in West Virginia, meaning flat roads are few are far between.
My XJ is a 1999 4.0 AW4 NP242 with 8.25" rear end (3.55 gears) on 235/75/R15's, No Trans Cooler (yet).
With this load should I tow in 3rd gear? Or can I tow in 4th? My XJ does not have the OD Off button. My grandfather seems to believe what I'm towing isn't a large load and that towing in 3rd would be a waste of fuel. I seem to think otherwise without a trans cooler.
If I can't tow in 4th with OD, if I invested in a transmission cooler would that suffice for towing this load in 4th with OD?
Any responses are appreciated!