Don there are major differences. The penalty will be gas mileage since the rpm's on your engine will be higher. The difference between my 3/4 van's towing capacity with the same 6.0 liter engine and 3.73 or 4.10 axle is 2,000 lbs. 7,900 lbs vs. 9,900. I'm glad I chose the 4.10 on mine. Jack