Illustrated Guide: Transmissions

Gears connect the two shafts to each other, and when one gear on one shaft meshes with one gear on the other shaft, the two shafts spin, effectively sending the engine’s power to the wheels. In neutral, the gears don’t mesh at all—meaning the input shaft and output shaft aren’t physically connected, and can spin freely of one another. You can see this simple example in the image above. Moving the shift lever controls which sets of gears are engaged with each other, effectively altering the gear ratio in use. The grey shaft connects to the wheels, and the yellow one contains the transmission’s gears.

Have you ever seen the inside of a transmission? Shafts, gears, cogs, passageways, pumps, bands, clutches and fluid lines are all packed into an incredibly small space, all working to turn the mechanical force generated by your ride’s engine into the miracle of forward momentum.

As far as most folks are concerned, transmissions operate on the principles of witchcraft and sorcery. Others know the important stuff: a transmission is a bunch of gears sloshing around in a bunch of fluid, and when you put it in ‘DRIVE’ the car moves.

By time you finish reading our guide, you’ll have a more comprehensive understanding, which will make you more educated, more awesome, and more appealing to the ladies (or blokes).

It wasn’t too long ago that a transmission had three or four gears, operated entirely without the use of computers, and was about as high-tech as a lentil salad. Today, transmissions are packing more and more gears into smaller and smaller spaces, using microprocessor-controlled computer systems to call the shots, and delivering higher levels of efficiency, performance and durability than ever.

Heck, automakers are starting to offer transmissions with seven, eight or even nine gears these days, even in mainstream models the masses can afford.

Here’s a closer look at the basic workings of the two most familiar types of transmissions: the automatic and the manual. We’ll take a look at some specialty transmission types, too.

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Justin Pritchard
Justin Pritchard is a native of Windsor, Ontario – though he’s called Sudbury his home for the past 20 years. Justin is a full-time auto writer, consultant and presenter of EastLink TV’s AutoPilot. His work can be seen weekly in numerous outlets across the country. When not writing about the latest new models and industry trends, you’ll probably find him fixing his 1993 Toyota MR2 GTS.
Justin Pritchard

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