Why does the car sound different in reverse?

When we drive, we are used to all the noises and sounds our car makes. We know it well and we know how it sounds. Any small change in the sound produced by the engine, or any slight variation in those noises, is noticed right away. That is why we notice that when we drive in reverse the sound of the car changes. The noise coming from the engine when reversing is not something strange; it is normal and has a reason behind it. So if you notice that your car makes a strange noise when engaging reverse, don’t worry, because we’ll explain why it sounds different.

How a gearbox works

The gearbox is one of the most complex elements of the car and is made up of several gears, which are permanently in contact with one another. But thanks to the movement of the gear lever, the gears change position, and their combination allows us to use one gear or another. The gears are helical, that is, they are set at an angle to improve contact and their efficiency. The friction between the different gears is thus smoothed out and offers better efficiency in operation. As a result, the noise they make from friction is also reduced.

Friction produces a sound, although it is usually very soft and goes unnoticed. But in the case of reverse§h22†, things change. The sound produced when engaging reverse and starting to move in this gear is different. It could be described as a zipper closing, because that is really what happens. The engine is constantly running, and it is the gears that allow the car to move forward or convert that motion so it can move in reverse. The gears that come into action when reverse is engaged have a different design, and this causes that characteristic sound.