I tow my race car on a trailer all over the country at about 3500 lbs total. I have no problems on most inclines. I do have to downshift going over the Rocky Mountains in Colorado. I do not tow in OD, I just leave it in 4th. I have trailer brakes but at 2600 lbs you should be able to get by without them if you are careful. I towed without trailer brakes for many years but was very happy that I converted to them.
You should have no problem power wise towing 2600 lbs with the 4.0 SOHC engine. You did not say if you have a automaitic or not but that would make it easier for you.
2002 FX4 Bright Red Supercab 4.0 SOHC, manual 5-spd & Tcase, 33" BFG MTs, K&N air filter, Modified air box inlet, Gibson SS cat. back exhaust, Bama flash, Hidden Hitch round receiver, Rear helper air springs, Electric trailer brake controller, Line-X bed liner, WAAG bar with KC lights and Wildernest shell.