It’s not a bad idea to remind ourselves occasionally of how manual and automatic transmissions work and how to use them—it’s a way to prevent errors that may prove costly. Here’s a refresher course.

Manual transmission

When starting your vehicle, it is strongly recommended that you shift to neutral and depress the clutch pedal all the way. In cold weather, this recommendation becomes an order! Even with the transmission in neutral, if the clutch isn’t fully disengaged, then half the gears are engaged. This places more strain on the starter, especially in cold weather, when oil thickens and offers greater resistance to movement. If that isn’t enough to convince you to follow this advice, then maybe the safety considerations involved will… And for what it’s worth, very few late-model cars with standard transmissions will start without the clutch being engaged.

The engine and transmission are for accelerating, the brakes are for braking

If you want to ensure engine durability, you should avoid using downshifting — also known as compression braking or engine braking — brusquely or on a regular basis, and reserve the technique for emergency situations requiring maximum stopping capability. You can, however, use downshifting to maintain speed (not decrease it) on an abrupt down slope. This involves choosing the right lower gear once the vehicle has lost enough speed that the engine won’t compress when you let out the clutch. When you compression-brake, you are downshifting into a lower gear (thus higher engine revolutions) in a fraction of a second. The technique imposes enormous stress on the vehicle’s powertrain (engine, transmission, drive shaft and differential). This can lead to specific problems such as excessive oil consumption, valve damage and, in extreme cases, a “blown” engine. Downshifting also exerts strong, unnecessary pressures on the universal joints as well as the engine mounts and the exhaust system. Moreover, vigorous compression braking on a slippery surface can lock your car’s drive wheels, which will almost certainly result in a skid. A final consideration: it costs far less to replace worn brake linings than a defective engine, transmission or clutch disc.

Neither handrests nor footrests

Some drivers tend to use the gearshift as a handrest, a bad habit in more ways than one: besides not keeping both hands on the wheel, they are needlessly putting pressure on the shifting forks. So keep your hand on the shifter just long enough to make your gear change.

Similarly, the clutch pedal isn’t meant to be used as a footrest (also known as “riding the clutch”). Each time you shift gears, make sure your right foot releases the accelerator completely: if you keep pressing, even lightly, the throwout bearing will remain in contact with the pressure plate—and rapid, excessive deterioration can result.

It’s also very important to take your time when shifting gears. If you shift too fast, and "grind the gears," it’s because you aren’t giving the synchromesh gears enough time to do their work—and they, along with the gears, will pay the price. Keep in mind that “faster than a speeding bullet” comes from a comic book, and should stay there.

Automatic for the people

With the arrival of a fourth and even a fifth speed, these days we have to pay a bit more attention to the transmission when driving an automatic. The top gear on these gearboxes, often called overdrive, should only be used at highway speeds, i.e., above 70–80 km/h (as with the top speed in a manual transmission). If you engage this gear at slower speeds, you can wind up with an annoying back-and-forth shifting between overdrive and the next lowest gear. Not only is it irritating, but the phenomenon can lead to—you guessed it—premature wear or even failure of the transmission.

Lastly, note that an automatic gearbox can work in the same way a manual one does to maintain and control a slower speed when descending an abrupt slope. It’s a matter of selecting the appropriate lower gear once you reach the right speed.