The simplest means to consider overdrive is to affiliate the phrase “overdrive” with the phrase “actual massive gear.”
As soon as you identify that psychological image, any confusion goes away. Overdrive means you might be utilizing the most important gear in your transmission to show the wheels, at excessive velocity. As a result of a giant gear has extra metallic tooth on it than a smaller gear, the large gear has to show much less (fewer RPM’s) to keep up the identical velocity as a smaller gear.
So, once you’re driving at a better velocity, it might stand to cause that you’ll get higher gasoline financial system since you are being powered by an even bigger gear that’s spinning much less. Overdrive lowers the engine’s RPM’s, and that saves fuel and put on on the engine. Overdrive is greatest for lengthy, flat stretches of freeway. I at all times kick into overdrive after I know the highway forward is just not hilly and I can drive uninterrupted at excessive freeway velocity, and I am not towing or carrying an additional heavy load.
It’s also possible to merely go away the overdrive change “on” and this may occur robotically. I like to recommend overdrive for speeds of 60 MPH or larger. When do you have to NOT use it? By no means use overdrive if you find yourself driving in hilly areas, towing one thing, or travelling very sluggish. You may truly injury your transmission for those who do. Bear in mind, a giant gear has to show much less to keep up the identical velocity as a smaller gear. So, at larger speeds the large gear is doing its job, pushing you effortlessly alongside an extended flat freeway at a gradual excessive price of velocity, and saving you fuel whereas doing it.
However once you’re travelling at slower speeds or stopping and beginning or going up and down hills or towing a automotive, it is much less about point-and-shoot excessive velocity journey and it is extra about having fast energy to speed up, or with the ability to navigate by way of hills or mountains, or with the ability to safely tow a heavy load. At a decrease velocity, the large gear would flip much less and fewer and lose its effectivity over the smaller gear.
You’d then must shift right into a decrease gear to generate sufficient RPM’s to supply energy to the wheels. Should you did not shift right into a decrease gear, you’d shortly really feel the larger gear struggling to energy the wheels and the RV would vibrate and lurch. You need to by no means use overdrive if you find yourself driving below these extra demanding circumstances. I go away overdrive off and manually flip the change to “on” after I journey on lengthy stretches of flat freeway.