There have been a lot of technological advancements, and breakthroughs in efficiency to make modern cars, trucks, and SUVs so much more fuel-efficient than their counterparts. While engine design certainly plays a huge role, automatic transmissions have come a long way as well, contributing greatly to the gas mileage of your vehicle. From Melvin's Auto & Truck Repair in St Augustine, FL, here are some ways transmissions have changed to meet the demands of fuel efficiency.