If you're like most drivers, you've probably come across the term "O/D off" while looking through your car's owner's manual. But what does it mean?

Simply put, O/D off is short for "overdrive off." Overdrive is a feature on many modern cars that allows the engine to run at a lower RPM than normal while cruising at high speeds. This results in better fuel economy and reduced engine noise.

However, there are times when you may want to turn off overdrive. For example, if you're towing a heavy load up a steep hill, you'll want the extra power that comes with a higher engine speed. Or, if you're driving in stop-and-go traffic, you may find that overdrive makes your car feel sluggish.

So, if you're ever unsure of when to use overdrive, just consult your car's owner's manual. And, as always, if you have any questions, feel free to ask your friendly neighborhood mechanic.