Watch How 4Hi, 4Lo, and 2Hi Change a 4WD Truck’s Performance

Most passenger cars on the market are equipped with front-wheel drive or rear-wheel drive (also known as 2WD). This means that the engine’s power is routed towards either the two front or back wheels of the car. It’s good for daily driving, but it sometimes lacks the power to deal with hazardous road conditions and definitely can’t handle off-roading. For that, you’ll need a car with either 4WD or AWD.

According to Edmunds, 45% of all new vehicles have one of these two drivetrains. 4WD cars have a transfer case with three different settings: 4Hi, 4Lo, and 2Hi. This allows the drivetrain to switch from 2WD to hi-gear or lo-gear 4WD. How does each of these settings enhance a 4×4’s vehicle’s performance? Here are the results from a test performed by Engineering Explained

Slippery terrain test

In the first test shown in the video, the car’s acceleration speed is tested over loose ground and a large puddle. The car used for the test is the Toyota Tacoma Sport. The 2WD mode was tested two times, once to include traction control and once without. In both settings, the driver experienced a lot of wheel slip while operating the Tacoma. With the traction control enabled, it was able to accelerate over the puddle in 2.8 seconds, and the driver found that the car was difficult to accelerate. It cleared the puddle in 2.47 seconds with the traction control off.

The Tacoma performed slightly better while using the 4WD modes. In 4Hi, the car was able to clear the puddle in 2.27 seconds. The driver found that it was much easier to accelerate the vehicle with 4Hi engaged. After shifting into 4Lo, the truck accelerated over the puddle in only 2.13 seconds. This mode also gave the driver the best torque performance, with a limited-slip differential of -27%.

Uphill test

In the second test, the driver tries to go over a hill at a very slow speed. The terrain is dry, which gives much more traction to the wheels compared to the previous test. During the uphill test, only the back wheels were used to supply power. In both 2WD modes, the Tacoma failed to lift itself over the hill. With the traction control off, the back wheels could spin more, but the left rear wheel received more power than the other.

The Tacoma’s performance slightly improved with the Auto LDS enabled, which is a feature exclusive to Toyota cars. It uses the traction control system to increase braking power and the engine’s overall performance. This helps the traction control function more efficiently because it brakes the slipping wheel and transfers more power to the wheel that has better traction.

2019 Toyota Tacoma TRD Pro
2019 Toyota Tacoma TRD Pro | Toyota

After the driver engaged the 4Hi mode, the Tacoma was easily able to go over the hill. The wheels didn’t slip throughout the maneuver even while traction control was disabled. When 4Lo was engaged, the Tacoma could accelerate the hill faster thanks to the extra torque. The maneuver was also smoother compared to 4Hi, and the driver was able to crest the hill without going over 1000 RPM.

The benefits of 4WD

As you can see from the video, having the option to switch from a standard drivetrain to a stronger one greatly enhances the power of the truck. Without the 4Hi and 4Lo modes, the truck wouldn’t be as stable while driving over loose terrain. With the addition of 4WD, the truck can operate more efficiently in all types of weather and is better suited for off-roading. It also gives the wheels more power so that they can go over big obstacles or tackle large bumps and hills.