The phrase "second gear" usually refers to a higher level of speed or effort. It means you are increasing your energy or intensity to tackle a task or activity.
Sentences with «second gear»
I was especially pleased when it started in second gear after a manual run. (autoweek.com)
That is somewhat unusual; in most vehicles, you shift into second gear at about 20 mph or so. (articles.orlandosentinel.com)
A great result without getting out of second gear for lots of the game. (untold-arsenal.com)