(Photo: R.M. Nunes/iStock)

AMA’s Guide to Powertrains

By Mark Richardson

Your vehicle has four wheels, but how many do you actually need—or want—to be powered by the engine? All of them or just a couple? And if it’s just a couple, should they be the wheels at the front or the back? If you’re in the market for a new vehicle, navigating powertrains can be tricky. There are four options for how your car or truck can drive its wheels—and each has pros and cons. Consider your needs and brush up on some powertrain terminology before making your decision.


This is usually the easiest and least expensive of the powertrains. The engine is at the front, so there’s no need for a long and heavy driveshaft that runs under the vehicle to the rear axle. The system is simpler and its lighter weight helps improve fuel economy. The weight of the engine over the front axle gives good traction to the driving wheels too.


When the rear wheels do the pushing, the front wheels can apply all their available friction to help you steer. This means a RWD car is normally more responsive and agile (and more fun to drive) than a FWD car.

A rear-wheel drive vehicle is also better at hauling heavy loads than its front-wheel drive counterpart, since pushing from the rear is more effective than pulling with the front. The heavier weight at the back also means there’s more traction for towing.


You get the best of all driving worlds when all four tires share the demand for acceleration, especially when a torque converter can send the engine’s power to one side of the axle or the other.

There’s better traction on snowy or wet roads, and performance cars can distribute their power more directly to whichever wheels can make the best use of it.However, all-wheel drive systems are heavier and more complicated, which can affect fuel consumption and maintenance costs. And while many drivers think they can brake better, all-wheel drive does little to help slow down your vehicle in slippery conditions.

To save fuel, most AWD vehicles drive power only to the front or rear wheels under normal conditions. When the road gets slippery or if you need quicker acceleration, the extra traction of the second pair of wheels is activated automatically, and instantly, to whatever strength is optimal.

The majority of systems can send up to half their power to the second axle, while some can also send power to just one wheel, if needed, in an extra slippery situation.

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The term “four-wheel drive” is becoming less common today. Now it usually refers to off-road vehicles with transfer cases that can switch the gears between high and low settings (like Jeeps and Land Rovers).

It used to be a vehicle that always powered all four of its wheels would be considered 4WD, but these days, some AWD vehicles will always send at least 10 percent of their driving power to the second axle—to be ready when it might be needed on an unexpectedly slippery road.

Still not sure which of the powertrains is right for you? Talk to the experts at an AMA Approved Auto Repair Service (AARS) partner. Look for the AARS sign at 118 partners in Alberta or visit ama.ab.ca/aars.