lately i have had to tow a 30ft gooseneck loaded about 12-14000 lbs, what setting should i be towing on? i have econo, daily, heavy tow and extreme. i was towing in heavy tow but dont have much power and i dont have guages so i dont want to run extreme, however daily seems to make my trans slam gears really bad. also can i run overdrive pulling this much weight? i always take it out of overdrive but my rpms are running high when i am doing 65-70.