Why do so many cars front traction make a sound when goes in reverse?

Question

cars like cavaliers, escort and others.....it could be an alarm to avoid hit someone?

Answer 1

If it is the unique loud whining sound you hear on manual transmission equipped cars when they are going in reverse, it is because reverse gear uses STRAIGHT cut gears, while the rest of the forward gears use helical, or angle cut gears that operate more quietly. Because on most (not all) manual transmissions, reverse gear is not "synchronized", the use of straight cut gears is necessary the enable to gears to slide into engagement along a shift rail, whereas the rest of the forward gears use a synchronizer and hub assembly to "lock" the selected forward gear onto the shaft. Heavy trucks (rigs) also use straight cut gears on their transmissions in ALL gears, which is why their operation is extremely loud. Hope this helps.

Answer 2

Do you mean the gear-whine when driving in reverse?

The gears for the forward gears in a manual transmission have angle-cut teeth so they run quieter

The gear for reverse has straight-cut teeth, so there's some gear noise or whine, especially if you're backing up fairly fast.

Automakers figure people aren't going to drive in reverse for very long, so they don't bother to angle-cut the gear teeth for the reverse gears.

If the forward gears whined like that too, there'd be a lot of complaining, so they angle the teeth on those so they're quiet.

Answer 3

most of these cars that you talk about is because they have a manual transmission. so the way its designed is diff from the automatics. in manuals, there are gears the provide the torque, this is where the whining sound comes from. in automatics, there is no gears but ATF auto. trans. fluid that does this work. thats why they are more silent. hope this answers your question