I'm currently towing a 5x8 uhaul cargo trailer loaded with a washer and dryer, 3 aquariums 75 125 and a plywood 200 gallon , and full with house hold items and clothes. Trailer is 900lbs empty can't really be more than 1000lbs of cargo. I'm about a few hundred miles in and currently driving in manual mode fifth gear is only 1800-2000 rpm at 60 depending on the grade fourth is leagues better just pulling along at 2500 rpm at 60. Sport mode is decent but hunts too much and too hard normal is just fifth and and occasional kick to forth but usually too late. My question is it ok to stay in fourth for long periods? 2005 l322 could it be the 33" tires lowering my gearing or the small cat weld exhaust leak causing me to lose valuable low end torque? Driving from Columbus Ohio to Miami fl by the way