please people. dont be stupid. lfs is a sim and u cant break the gearbox per say, but that's no reason to use it for slowing the car down, btw you're not actually using the gearbox, it's the engine friction (and not engine compressions as it's popullary belived).
what you are actually doing (if you are using the engine for braking) is hindering accurate brake modulation and balance - i.e. ur not braking properly or on the limit. IF you are braking on the limit, adding the engine friction will only cause u to lock up and lose traction - not a desired effect. the reason for rapid downshifting is the sequential gear change (u have to go trough all the gears from 6th to 2nd), if you are in your real life car, ideally u would shift maybe 2 gears down or even 3 at a time, but not like 6th to 2nd or 1st (well shifting to 1st is best done from a gear not requireing a cross-gate shift - but that's just due to gearbox design). the reason for downshifting is just so that u can be in a proper gear for the corner exist (in the ideal rpm range for max torque bla bla).
next time u use the engine for slowing the car down, remember u are beeing stupid and scipy said so. you are only upsetting the balance of the whole car and not using the brakes effectivley. btw when u downshift u better be blipping the throttle to match the engine rpm with the gearbox rpm - so the car doesnt nosedive - if you are doing that, then ask yourself why to **** would u be doing that if u wanted to use the engine for braking. i am sick and tired of stupid and ignorant people: this actually include real life car mechanics, real life race drivers, my dad, his dad, my friends, their dads, many "street races" i know and most of the sim world. i am also sick and tired of false arguments that my dad gives me: "i've been driving for almost 30 years and i've been doing it like this". <- THAT DOES NOT MEAN U ARE DOING IT RIGHT. the whole car industry prays on stupid people who are braking their engines and clutches by using them for what they have not been constructed.
p.s. i am studying to be a mechanical engineer (2nd year now)
p.s.s. engine braking can be used in snow or ice conditions to make the tire rorational speed lower then the relative speed of the car so that u can keep some kind of control over steering.
END OF DISCUSSION