Gearshift Vacuum Control 1938 Chevrolet Division, General Motors (Patreon)

more at http://quickfound.net/

AN EXPLANATION OF THE PRINCIPLE OF THE NEW VACUUM GEARSHIFT, AND HOW IT CONTRIBUTES TO COMFORT, EASE OF DRIVING, & SAFETY.

Originally a public domain film from the Library of Congress Prelinger Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

Print ad for new vacuum gearshift:

https://books.google.com/books?id=5UEEAAAAMBAJ&lpg=PA20&ots=XPAXtTHVXQ&dq=chevrolet%20vacuum%20gear%20shift&pg=PA20#v=onepage&q=chevrolet%20vacuum%20gear%20shift&f=false

https://en.wikipedia.org/wiki/Gear_stick

Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/

A gear stick (rarely spelled gearstick), gear lever (both, UK English), gearshift or shifter (US English) is a metal lever attached to the shift assembly in a manual transmission-equipped automobile and is used to change gears. In an automatic transmission-equipped vehicle, a similar device is known as a gear selector. A gear stick will normally be used to change gear whilst depressing the clutch pedal with the left foot to disengage the engine from the drivetrain and wheels. Automatic transmission vehicles, semi-automatic transmissions, and those with continuously variable transmission gearboxes do not require a clutch pedal...

Some vehicles have a column shift where the lever is mounted on the steering column—this arrangement was almost standard practice in American vehicles from about 1939 until relatively recently. It had the added benefit of allowing for a full width bench-type front seat...

https://auto.howstuffworks.com/1937-1939-chevrolet5.htm

Perhaps the most interesting new feature of the 1939 Chevrolet was the "vacuum gear-shift," a $10 option that appears to have been fitted to most of the 1939s. A short lever was mounted behind the steering wheel, leaving the floor free from the then-familiar obstruction of the shift lever...

Chevrolet claimed that "80 percent of the effort required for shifting is provided by a vacuum cylinder." Light pressure of the fingertips was all that it took to change gears. Chevrolet retained this feature through the 1948 season, supplying it as standard equipment commencing in 1940.

However, quite a few owners complained that in time the vacuum mechanism ceased to function and shifting gears became stiff and cumbersome...