What You Need to Know About Toyota’s Hybrid All-Wheel Drive System

  • Jeff Sabatini has written for many publications over his 20 years in automotive journalism, including Car and Driver, the New York Times, the Wall Street Journal, and Sports Car Market magazine. His lifetime car churn includes 30 vehicles: eight GM cars, five Ford products, four Toyotas, three BMWs, two Jeeps, two Chrysler minivans, a Miata, a Mercedes, a Porsche, a Saab, a Subaru, and a Volkswagen.

can be reached at jeffsab@gmail.com
  • Jeff Sabatini has written for many publications over his 20 years in automotive journalism, including Car and Driver, the New York Times, the Wall Street Journal, and Sports Car Market magazine. His lifetime car churn includes 30 vehicles: eight GM cars, five Ford products, four Toyotas, three BMWs, two Jeeps, two Chrysler minivans, a Miata, a Mercedes, a Porsche, a Saab, a Subaru, and a Volkswagen.

can be reached at jeffsab@gmail.com
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Toyota sells hybrid versions of both its RAV4 and Highlander SUVs. Both offer good value for the money, with roomy cabins and long feature lists, including all-wheel drive. But the hybrids have radically different all-wheel-drive systems than on the non-hybrid models. How do these electric systems perform compared to their conventional counterparts? We tested them back-to-back.

  • The RAV4 Hybrid and Highlander Hybrid have a unique all-wheel-drive configuration that uses an electric motor to turn the rear wheels.
  • Non-hybrid models come with a conventional all-wheel-drive system, in which front and rear axles are connected with a driveshaft.
  • Higher trim levels of the non-hybrid RAV4 have a more sophisticated all-wheel-drive system that can also do side-to-side torque vectoring for improved performance.

Toyota RAV4 HybridThe 2020 Toyota RAV4 Hybrid uses a 40 kW electric motor to drive its rear wheels, rather than a conventional driveshaft. (Photo: Toyota)

Giving up the driveshaft

A 2.5-liter four-cylinder engine sits under the RAV4 Hybrid’s hood, mated to a transaxle that contains two electric motors. A small, nickel-metal-hydride battery resides under the rear seat, which powers the electric motors as well as storing electricity that’s regenerated under braking. A third electric motor is mounted under the rear cargo compartment; there is no driveshaft connecting the front and rear wheels. All told, the RAV4 Hybrid makes 219 horsepower. The Highlander Hybrid uses a similar system, but with 243 hp.

Below 15 miles per hour, the rear motor in the RAV4 Hybrid is always engaged to increase low-speed traction, turning a standard mechanical differential connected to the rear axle. Above that range, the vehicle’s computer calculates when it should apply power through an electromagnetic clutch; wheel slippage is not necessary for the system to engage. The computer also decides when it should spin the electric motor in reverse for additional regeneration during deceleration.

Toyota RAV4The 2020 Toyota RAV4 TRD Off-Road has a sophisticated all-wheel-drive system that can route power sent to its rear axle from side-to-side. (Photo: Toyota)

The conventional alternative

Non-hybrid RAV4 models are also motivated by 2.5-liter four-cylinder engines, making 203 horsepower without the electric motors. Rather, an 8-speed transaxle spins the front wheels, while all-wheel-drive models also have a driveshaft connected to a rear axle and the rear wheels. The simplest version of this system employs a single electromagnetic clutch in the transaxle to control whether power is routed to the rear or not; the default is for just the front wheels to be powered.

The more sophisticated all-wheel-drive system, which is shared with higher trim levels of the Highlander, has two clutches in its rear differential to allow power to be routed to one side or the other or both at the same time. Two additional clutches, in the transaxle and the rear differential, allow for the entire system to be disconnected from the engine for greater fuel efficiency. But it’s that ability to send power to just one of the rear wheels, called torque vectoring, that give this all-wheel-drive system its greater capability.

2020 Toyota RAV4

A snowy course was the perfect venue to test Toyota’s hybrid all-wheel-drive system. (Photo: Toyota)

Putting it to the test

This all begs the question: How does the hybrid all-wheel-drive system perform in the real world compared to the torque-vectoring system in the non-hybrid? At a recent event, Toyota allowed us to test the RAV4 Hybrid back-to-back against the RAV4 TRD Off-Road equipped with the dynamic torque vectoring all-wheel-drive system. We drove both vehicles on a snow-covered course, including a standing start test on a slippery grade. Spoiler alert: The RAV4 Hybrid acquitted itself quite well.

Neither vehicle had difficulty accelerating up the hill without excessively triggering its traction control system. The RAV4 Hybrid did require a much lighter touch on the throttle, as the instant torque of its rear electric motor could easily overpower its all-season tires. And once the RAV4 Hybrid’s traction control kicked in, it more aggressively cut the power than in the non-hybrid model, which was much more lenient about spinning its wheels.

2020 Toyota RAV4 TRD Off-RoadThe TRD Off-Road RAV4 had slightly better all-season tires than the RAV4 Hybrid, which its torque-vectoring all-wheel-drive system made the most of. (Photo: Toyota)

Enthusiast-grade

Navigating the slippery course, the aggressive traction control of the hybrid kept us from sliding into the deep snow. Even when we tried to apply power to “drift” the rear end of RAV4 Hybrid into rotating around a corner, the computer was having none of it. Instead the RAV4 Hybrid calmly understeered straight forward to a stop every time – which is what you want a vehicle to do in extremely slippery conditions. The opposite, oversteer, can result in the vehicle going into a dangerous spin.

The RAV4 TRD Off-Road did corner better without sliding, and not just because of having slightly more grip from its better grade of all-seasons. We could certainly feel the rear axle delivering more power to the outside rear tire while cornering, helping to push the nose of the vehicle around the turn. The dynamic torque vectoring really works, and made it easier to drive the RAV4 at higher speeds around the course.

2020 Toyota Highlander HybridThe 2020 Toyota Highlander Hybrid uses the same all-wheel-drive configuration as the smaller RAV4 Hybrid. (Photo: Toyota)

The verdict

For the vast majority of buyers, the all-wheel-drive capabilities of the RAV4 Hybrid should be more than enough. The advantages of torque vectoring all-wheel-drive are mostly going to apply to enthusiasts and those who spend considerable time driving in the worst snowy and rainy conditions. But the fuel economy advantage of the hybrid RAV4 is so substantial – 40 miles per gallon combined against just 28 miles per gallon – that we can’t see passing on the hybrid in favor of the better all-wheel-drive system.

For the Highlander, there are other reasons to choose a model with dynamic torque vectoring – principally the greater power of its V-6 engine. The decision is also complicated by the front-wheel-drive Highlander Hybrid, which is a less expensive way to get into the most efficient hybrid at the sacrifice of all-wheel-drive. That said, the hybrid all-wheel-drive system in the Highlander is excellent. Delivering 35 mpg – a 12 mpg improvement over the non-hybrid – makes the Highlander Hybrid just as compelling as the RAV4 Hybrid.



About the Author

  • Jeff Sabatini has written for many publications over his 20 years in automotive journalism, including Car and Driver, the New York Times, the Wall Street Journal, and Sports Car Market magazine. His lifetime car churn includes 30 vehicles: eight GM cars, five Ford products, four Toyotas, three BMWs, two Jeeps, two Chrysler minivans, a Miata, a Mercedes, a Porsche, a Saab, a Subaru, and a Volkswagen.

can be reached at jeffsab@gmail.com
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