Can the snowmobile mode of the automatic gearbox be used to help the car get out of slippery terrain such as mud?
Should not the automatic snow-shift changes in the city be more economical, since they start in second gear? – Rodrigo Jacomelli Simas, Porto Alegre (RS).
The two questions are related, so let’s answer them together.
The snow mode offered in some cars with automatic gearboxes is usually triggered by a button that bears the symbol of a snowflake. In cases of vehicles with driving mode selector, it can be identified by the word “snow”.
In practice, it changes the programming of the automatic gearbox to make the vehicle leave the immobility in second gear with smoother acceleration. This feature reduces the tendency for the wheel to rotate in a false start, but as soon as it starts moving the gear changes are made in the traditional model.
The mode must only be activated when the vehicle is stationary on low-adhesion floors. In Brazil and in countries where snow is very rare, it can also be used in mud or on slippery surfaces, such as wet grass.
On the possible fuel economy, the answer is no. Since the gearbox uses a higher gear (second or third gear) to allow it to come out of low-grip situations without skating, under normal conditions (such as in the city) this would only make the start slower.
In addition, it could instigate the driver to push the throttle further to compensate for the lack of force at start-up, which would force the engine out of its optimal spin range, consuming more fuel than if the output were made in the first gear.