I use tow/haul all the time when towing, but my trailer is heavier than yours. When going down long grades, start slow and manually shift the tranny into the lower gears. Pump brakes as needed. I've towed with mine all over hills and mountains. No over heating of engine or tranny. Only weak point I know of is the brake rotors. My OEM rotors warped from the heat of towing. I replaced with high performance EBC brake rotors and pads. Now, no problems.
2000 Cherokee 31BH, "flipped axles and raised",LEDs, solar, inverter, etc..aka "boondock ready". '07 Tundra 5.7L DC-LB, modded as well.
2000 Cherokee 29BH with 6V batteries, LED lights & 400 watts of solar power, flipped axles and raised. 2007 Tundra 5.7L DC-LB with lots of mods. C-co, 8/158th AVN Maint.