Here is how to use overdrive in a GM Chevrolet automatic transmission on a Chevy truck. On a Chevrolet truck, overdrive gear is only supposed to be used under light loads on relatively flat roads. If you are climbing steep hills, or if you are hauling a heavy load or pulling a trailer, then you should put your truck automatic transmission into third gear instead of overdrive. Only use overdrive for light driving conditions, and if you’re doing anything intense, put in third gear. If you learn how to properly use overdrive gear on your Chevrolet truck, then your transmission will last longer, and your truck will work better. The truck in this video is a 1995 Chevrolet Silverado Z 71 4 x 4. This video shows when to use overdrive in a truck.