In gear and In a job

In gear adjective - Having gears engaged.

In a job and in gear are semantically related in active topic. In some cases you can use "In a job" instead an adjective phrase "In gear", when it comes to topics like working.

In gear and in a job are semantically related in active topic. You can use "In gear" instead an adjective phrase "In a job", if it concerns topics such as working.