What's the Overdrive for?

[catsy]

I'm sorry if this topic is too general but I have a 95 Hyundai Accent that has the overdrive feature and I've been told it's for different things.

I was told it is to be used when I drive the highway at high speeds.
Then I was told by someone else that it's only to be used if I'm hauling heavy loads (which sounds ridiculous since anyone who's seen a 2-door 95 Accent doesn't see how much of a load could be put in or on one).

So, what IS it for?

Thanks so much!!

[MagicRat]

Highway speeds when you are NOT hauling heavy loads.

Generally, any steady cruising over approx. 45 mph will benefit from using the overdrive.

You can leave the overdrive "switched on" all the time. The transmission will only engage it when its needed. You would only switch it "off" when you are driving at highway speeds in hilly terrain and/or hauling heavy loads.