Back in the 1980s, I was lent for about a year a small sporty car that had overdrive. I think that was the only car I've ever driven for an extended period that was fitted with it. It was operated electrically by a button on the gear knob. Being an English car, it amazed us by working - most of the time. Whether it produced better fuel economy on the long country drives was another matter - I didn't notice any improvement. However, I'm sure it allowed car salesmen to shift a few more units of product.
I'll have to think of some more words that no longer really have a contemporary meaning. Whilst people still talk about shifting into overdrive, the overdrive itself is long gone as a useful product.