Torque shop: Transmission types

Apart from periodic clutch replacements, there is not much else that wears out in a manual gearbox.
Apart from periodic clutch replacements, there is not much else that wears out in a manual gearbox.PHOTO: MINI

SINGAPORE - There are various transmission types used in passenger cars. Which is the best in terms of overall performance and reliability? Perhaps the most robust of all transmissions is still the manual gearbox, which is rarer these days than an airborne passenger aircraft.

Apart from periodic clutch replacements, there is not much else that wears out in a manual gearbox.

The classical automatic transmission with a torque converter has competition from the continuously-variable transmission (CVT) and double-clutch gearbox.

All these transmissions tend to require major maintenance at around the 100,000km mark.

By then, double-clutch transmissions require a new clutch pack, which costs three times more than the clutch set in a manual gearbox.

One issue which has plagued some double-clutch gearboxes is the mechatronic control unit. They are expensive to replace and failures are somewhat unpredictable. Fortunately, the current generation of mechatronics is of much higher quality and hence far more reliable.

Several Japanese and Korean small and medium car models now come with CVTs, making them the second most common automatic transmission. CVT reliability was an issue when they first started appearing in the late 1980s. Today, they are almost as reliable as torque-converter autoboxes.

The traditional automatic transmission has had the benefit of constant development over some eight decades and continue to be the first choice for most car makers. It is responsive, efficient and highly reliable.