Fareed's Auto Service Blog: Tips, Advice and More

Hello and welcome! My name is Fareed, and this blog is about car repair. I plan to write about smash repair, body work, painting and other aspects of the industry. I also hope to include a few posts that will help you assess whether or not something is wrong with your car. I have worked on my own car for years, and recently, I've been embraced as the neighbourhood mechanic -- all my friends come to me for help. I'm not a professional mechanic, but I feel confident sharing this info with you as I've been working on cars for years. I am happy you found my blog and hope that you enjoy reading!

Getting the Difference between 4WD and AWD Transmissions


The drivetrain or powertrain comprises a system of components that work together to power a vehicle so that it moves. One of the major components of the drivetrain is the transmission that converts the power of the motor into the force that makes the wheels to rotate. Vehicles come in different transmission set ups that include the four-wheel drive and all-wheel drive systems. Many new vehicle owners are usually unable to tell the difference between these two types of drivetrains and usually confuse one for the other because "four" wheels may mean "all" wheels if taken literally. Here's a rundown of how each of the transmissions functions and what driving conditions they are best suited for. 

4WD Transmissions

Also known as four by fours, 4WD systems are the older of the two systems. As their name suggests, they function by powering each of the four wheels. 4WDs have a unique component called a transfer case, which works in tandem with two differentials (front and rear axle differentials) to evenly split torque and send it to the four wheels. Torque is the rotational force that is transferred from the transmission of the vehicle.

When the 4WD system is engaged, it locks the front and rear axles together. This provides the vehicle with excellent traction, but there's also a downside to it. A vehicle that's locked in four by four is not suited for normal-road driving because both the front and rear axles rotate at similar speeds. This may cause the vehicle to easily spin out of control when it is being operated on flat, dry road surfaces. That explains why you never really see people using 4WDs when driving on the freeways and highways. Instead, you will see them driving their vehicles in deep snow or for other different kinds of off-road driving. Generally speaking, 4WD is reserved for pick-up trucks and truck-based SUVs, which require maximum traction for off-roading applications.

The 4WD feature can be turned OFF so that the vehicle runs in 2WD mode. This can be done by pressing a button on the dashboard or by getting out of the vehicle to manually lock the front wheel hubs. 

AWD Transmissions

AWD and 4WD transmissions are designed to do the same thing, but in different ways. AWD is a newer addition to automobile mechanics and it is mostly found in cars. Like 4WDs, AWDs have a transfer case and a differential placed between the front and rear axles. But unlike 4WDs, an AWD drive system has an additional component called the centre differential, which powers the wheels with the most traction by evenly splitting torque between the front and rear axles. In addition, AWDs are constantly (or mostly) turned on. AWD transmission cars are ideal for freeway or highway driving, and not for off-roading — that's the domain of vehicles with 4WD vehicles.


22 May 2017