1. Our guinea pig is the same '96 Chevy C3500 dually tow pig that you read about in past issues of Sport Truck. It's frequently ridden hard and put away wet and used daily for commuting purposes. We routinely run conventional 10W-30 gear oil in the 7.4L Vortec big-block Chevy, ATF in the 4L80-E transmission, and 75W-90 gear oil in the Corporate 14-bolt rearend. After three baseline pulls by "Jersey" Steve on Westech's dyno to find a power average, we got crackin' and put the truck up on the lift.