Streaming TV shows and movies directly to your home is a breeze with Netflix. As a Netflix member, you can instantly watch TV and movies on your PC, Mac, mobile device, or right on your television. Get a free thirty day trial membership. Go to Netflix dot com, slash brain Stuff and sign up today. Welcome to brain Stuff from house stuff works dot com where smart happens. Him Marshall Brain with today's question, why does a manual transmission make a loud,
worrying noise when it's put into reverse? Manual transmissions use mostly helico gears, but reverse is a special situation that requires a different type of gear, a spur gear, and this is why reverse sounds different than forward in a normal manual transmission car. The gears that make up the forward gear ratios are all helical gears. The teeth on helico gears are cut at an angle to the face
of the gear. When two teeth on a helical gear system engage, the contact starts at one end of the tooth and gradually spreads as the gears rotate until the two teeth are in full engagement. This gradual engagement makes helical gears operate much more smoothly and quietly than spur gears do. Also, because of the angle of the gear teeth, more teeth are in engagement at any one time. This spreads the load out more and it reduces stresses, which
also reduces noise. The only problem with helical gears is that it's hard to slide them in and out of engagement with each other. On a manual transmission, the forward gears stay engaged with each other at all times, and callers that are controlled by the stick shift lock the different gears to the output shaft. You can go read how manual transmissions work for details on this. In contrast to that, the gears that are used in reverse are normal gears like you see in cartoons their circles with
teeth on them. The reverse gear on your manual transmission uses an idler gear that has to slide into mesh with two other spur gears at the same time in order to reverse the direction of rotation. Each time a gear tooth engages on a spur gear, the teeth collide instead of gently sliding into contact as they do on helico gears. This impact makes a lot of noise and
also increases the stresses on the gear teeth. When you hear a loud, whirring noise from your car and reverse, what you're hearing is the sound of the spur gear teeth clacking against one another. For more on this and thousands of other topics. Because it how staff works dot com, Streaming TV shows and movies directly to your home is a breeze with Netflix. As a Netflix member, you can instantly watch TV and movies on your PC, Mac, mobile device, or right on your television. Get a free thirty day
trial membership. Go to Netflix dot com slash brain stuff and sign up today.