manual transmission vs steering wheel

manual transmission

noun
  • A multi-speed vehicle transmission, where gear changes require the driver to manually select the gears by operating a gear stick and clutch (which is usually a foot pedal for cars, or a hand lever for motorcycles). 

steering wheel

noun
  • A wheel-shaped control that is rotated by the driver to steer, existing in most modern land vehicles. 

How often have the words manual transmission and steering wheel occurred in a corpus of books? (source: Google Ngram Viewer )