“Greetings from the gearbox” and “shifting is not a secret” are typical sayings from outsiders or passengers who have just heard a loudly crunching gear change. Such maneuvers are actually not that funny, because the crunching can almost be understood as a scream of death from the gearbox. Once the transmission is broken, repair costs in the clearly four-digit range are the rule rather than the exception.
Shift through the gears too quickly
Especially in films, you can often see drivers shifting from one gear to the next in less than a second. What may really help the dramaturgy of the film is not so well received by the manual transmission. Inside a gearbox, there are gears, which are usually of different sizes and (to put it simply) take care of the different gears.
Engage reverse gear when the car is rolling
The reverse gear ensures that the wheels turn in a different direction. So that this can happen, there is a separate gear especially for reverse gear in the gearbox, which is coupled to another gearbox via the gearshift sleeve. This gear is usually not synchronized (unlike the forward gears). Therefore, the car should standstill before engaging the reverse gear.
Place your hand on the gear lever
It is not only popular among amateur racing drivers to simply put their right hand on the gear lever. But in the long run, this supposedly cool gesture also damages the transmission. If you always keep your hand on the shift lever while driving, you automatically put a strain on the shift sleeve. This pressure on the gearshift sleeve creates a kind of tension in the gearbox, which not only puts a greater strain on the gearshift sleeve, synchronizer rings, and the coupled gears and thus also wears out faster, the gearbox bearings also suffer. Keep your hands on the wheel while driving. This is not only good for the transmission, but also for your own safety.
Clutch not pedaling properly
Another mistake with fast, sporty shifting: The clutch pedal is not pressed correctly or not in time. This little carelessness can also lead to really expensive repairs. If the clutch does not completely separate the frictional connection between the engine and the transmission or does not separate it in time and you still shift to the next gear, the transmission often reacts with a loud crunch. This grating is caused by the fact that the synchronizer rings are not able to bring the two gears up to speed during the switching process. While one gear rotates at wheel speed, the other rotates at engine speed and cannot be braked. If you then switch, the gearshift sleeve is forcibly pushed onto the gearwheels of different speeds.
To ensure that the gearbox stays fit for a long time, it should be subjected to regular maintenance. A lot of car manufacturers do not even plan to maintain transmission. Especially when it comes to gear oil (regardless of whether it is a manual gearbox or automatic), there is very often the “lifetime filling” clause.