This is what the 'O/D' button stands for and most people have no idea what it means
Published on Sep 09, 2026 at 3:35 PM (UTC+4)
by Alessandro Renesis
Last updated on Sep 09, 2026 at 3:35 PM (UTC+4)
Edited by
Ben Thompson
If you drive an automatic vehicle – especially older cars and trucks – you may find a small button on or near the gear shifter labeled O/D.
While plenty of drivers see this button every day, a surprisingly large number have no idea what it actually does.
They also don’t know when to press it, or why it exists in the first place.
But it actually serves a very useful purpose.
What does ‘O/D’ stand for?
O/D actually stands for overdrive, which is the highest gear in an automatic transmission, and also a cool song by Drake, if that’s your jam.
In standard lower gears, the engine turns faster than the wheels to provide torque and acceleration.
In Overdrive, the gear ratio is inverted: the transmission allows the driveshaft to spin faster than the engine crankshaft.
So basically, in simple terms, Overdrive allows your car to cruise at high speeds (like on the highway) while keeping the engine’s RPM low.
In addition to saving you from going deaf, this also means you’ll be using less fuel, which is nice.
How the O/D button works
By default, Overdrive is turned ON in almost all automatic trucks and cars, and you don’t need to do anything about it.
But you can turn it off, of course.
However, since Overdrive saves fuel and lowers engine wear during normal driving, there’s generally no reason to turn it off.
But with exceptions.
If you’re towing heavy loads, for example, you might need the extra power and torque, and disabling Overdrive will help.
It’ll also help while driving down steep hills, because turning Overdrive off will engage engine braking, which is essential in similar scenarios.
The same goes for slippery or icy roads.
But to be honest, we’re preaching to a choir that’s on its way home because Overdrive is already largely extinct.
Modern cars do everything automatically and electronically, and that has been the case for a while.
So this means that within the decade, almost no car left on the road will feature an Overdrive button.
Alessandro is an automotive journalist with 10 years of experience covering supercars, automotive history, emerging vehicle technology, and luxury transportation. He wrote the first article published on SupercarBlondie.com when the website launched in 2022 and has since built a reputation for insightful reporting across the automotive and transportation industries. His expertise is grounded in hands-on experience. Alessandro has driven every Tesla model ever produced, from the original Roadster to the Cybertruck, and regularly covers the latest developments in electric vehicles and automotive innovation. His passion for transportation extends beyond cars, he has even flown a Boeing 787 Dreamliner simulator in Addis Ababa, Ethiopia. His reporting spans everything from classic American muscle cars and rare automotive discoveries to luxury yachts, private aircraft, high-end watches, and cutting-edge vehicle technology. Known for his deep knowledge of automotive history and ability to uncover the stories behind iconic vehicles, Alessandro brings readers a blend of historical context, technical expertise, and first-hand experience.
