my dealer told me that the gear ratio would be the same unless i engaged the tow mode. if i do not have the tow mode engaged, is it affecting my gas mileage. i wanted the towing mirrors and he told me i could not just get the mirrors and put them on a truck that did not have the package for them. not that i am too obsessed about gas mileage. i bought a big truck. i was just wondering if i was taken for a ride. if the gas mileage is very different i may consider trading down.