Transmission

How To Downshift An Automatic Transmission: When, Where and Why?

Learning how to downshift an automatic transmission might seem like a strange skill to acquire. After all, isn’t the entire point of an automatic to not have to do any of that work while you’re cruising around? You’d be right with that assumption, but there are many kinds of auto gearboxes on the market today, with some offering the chance to get more involved in the driving process. There are also a few instances where knowing how to downshift an autobox could help you out of a tough situation.

Why Downshift?

There’s one main reason why you’d want to downshift an automatic transmission: to select the right gear for the driving situation you’re facing. In most cases the computerized brain that controls you transmission is going to be light-years ahead of you in determining which cog should be up next while you’re on the road. However, that same computer doesn’t have access to your eyes and ears, and so it can’t see what’s coming up ahead.

Low Gear For Low Traction

Low gearA perfect example is when you find yourself dealing with a low-traction situation. If you’re slipping through mud, or trying to get yourself out of a snowbank, it doesn’t do any good for your automatic transmission to spin the wheels through three gears if you’re not moving forward. Downshifting to first or second gear — sometimes labeled as “L” on your gear selector — can help you find the grip you need by keeping torque under control.

Starting out in a lower gear and benefiting from all of that torque multiplication can also be a big help when towing a heavy trailer, or when trying to help slow that same load down in conjunction with your brakes.

Dual-Clutch Performance

The proliferation of dual-clutch “automated manual” transmissions give you another reason to learn how to downshift. These gearboxes feature a pair of internal clutches instead of a traditional torque converter automatic, which allows them to pre-select the next gear and offer lightning-quick changes at speed. Downshifting one of these transmissions — usually with a steering wheel-mounted paddle — is very similar to using a standard manual transmission, only without a clutch pedal, and often with automatic throttle-blipping to smooth everything out. Think of it as a high-performance manual box that will also shift itself when you don’t want to get involved, like when you’re sitting in rush hour traffic.

Downshifting an automatic transmission can be a practical skill, if you also learn when and where to use it. Low-traction situations, towing or just having fun in a dual-clutch sports car are all scenarios where you might want to manually intervene in the shifting process, giving you more control over power delivery and letting you get that much more involved in the task at hand.

For more information on your automatic transmission, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Freeimages

about author

Benjamin Hunting

Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time.  I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.

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