In a turn, the outside wheel travels farther and faster than the inside one. That’s because it doesn’t have a differential. The differential is a device that splits the engine torque two ways, allowing each output to spin at a different speed. Your vehicle does, however, whether it’s front-, rear-, four-, or all-wheel-drive. What type of differential you have, and even how many, depends on what you’re driving?
The differential is a set of gears that transmits engine power to the wheels while allowing them to turn at different speeds on turns.
With front-wheel-drive (FWD), the differential is alongside the transmission inside a housing, and the unit is called a transaxle. With rear-wheel-drive (RWD), the differential is between the rear wheels, connected to the transmission by a driveshaft. All-wheel-drive (AWD) and four-wheel-drive (4WD) vehicles add a center differential or transfer case to distribute power front and rear.
Some hybrid vehicles have “electronic” AWD. These use electric motors to power the rear wheels and turn them faster or slower as needed on turns.
The differential is found on all modern cars and trucks, and also in many all-wheel-drive (full-time four-wheel-drive) vehicles. These all-wheel-drive vehicles need a differential between each set of drive wheels, and they need one between the front and the back wheels as well because the front wheels travel a different distance through a turn than the rear wheels.
Part-time four-wheel-drive systems don’t have a differential between the front and rear wheels; instead, they are locked together so that the front and rear wheels have to turn at the same average speed. This is why these vehicles are hard to turn on concrete when the four-wheel-drive system is engaged.
A differential is a gearbox that is found between the drive wheels of your vehicle. If your vehicle has a four-wheel drive system, then it more than likely has a front and rear differential. A differential works with the transmission to deliver power from the engine to the axle that turns the wheels.
It also helps your vehicle turn properly. In order for your vehicle to turn, the outside wheels must turn faster than the inside wheels. A differential uses gears to enable the wheels to turn at different speeds.
In simple terms, a differential is a system that transfers the torque from an engine to the wheels. The differential takes the power from the engine and divides it so that the wheels can spin at different speeds. Rotate it around a corner and you won’t have any problems as each wheel can turn independently from the other.
When you look at a complete modern differential, it looks incredibly complicated.
However, if you systematically break it down and understand the basics of what it is trying to achieve and how it is trying to achieve it, you will find that it is really a beautiful thing.
Check out this video of Chevrolet engines for a retro look at the differential.
Now that we understand the basics of a differential, or in this case an “open differential,” let’s discuss a little more about a limited-slip differential (LSD).
Imagine you are on the track trying to get out of a tight corner at 50km/h. All of this power will take the path of least resistance.
All weight has been shifted to one side. All of that power will only spin the inner wheel, resulting in a tremendous amount of power lost or spinning and a major crash.
The LSD is in place to minimize this drive loss. A clutch system creates friction on each side of the axle so that the car can redistribute torque to each wheel so you can get as much power as needed. If you know your way around the wheel, you can steer the car with nothing but power, even in a curve.
As you can imagine, the entire differential mechanism has to withstand an enormous force. This is just one reason why these components are made from the strongest possible materials. No straws and milk bottle caps.
Differentials have to be extremely durable. When cars were slower and less demanding, you could get away with cheaper metals. This is simply no longer the case.
Even today’s simplest vehicles can travel comfortably at over 150 km/h and are capable of safely cornering at relatively high speeds. High-quality components are no longer reserved for the racetrack.
Following are Differential Parts:
There are four common differentials used between vehicles – open, locking, limited-slip, and torque-vectoring.
Here are the four types of differentials:
This type of diff is the most basic and only allows for variations of individual wheel speed or slip but that’s it. In optimal road conditions, it allows the outside wheel to rotate faster than the inside wheel. The problem is when road conditions are not ideal such as on wet pavement, ice, snow, or gravel.
With an open diff, the engine torque still transfers even if the wheel has zero traction so that the slipping tire will simply spin and not go anywhere.
Open differentials are found in most vehicles on the road today so generally speaking, the cost to repair the differential is less than other diff types (if same axle).
Under ideal road conditions, a limited-slip diff acts just like an open diff and transfers torque independently to each wheel.
But, under hard cornering or heavy acceleration where an open diff would generally cause a tire to slip, a limited-slip diff prevents the normal amount of torque to go to the slipping tire (the one with the least resistance).
It does so through the use of clutches and plates within the differential. This enables the vehicle to power through corners a vehicle with an open diff would struggle with. Race cars and other performance vehicles (as well as some off-road vehicles) use limited-slip differentials.
Found on many off-road vehicles and some performance cars, locking differentials use clutches and springs to activate a lock which sends an equal amount of power to each wheel no matter the traction situation. This essentially creates a fixed axle.
The benefit is the locked diff’s ability to gain a greater amount of traction since the full amount of torque is always available to a wheel and not limited by the lower traction of one wheel.
At higher speeds this is a negative but when off-roading or rock climbing, it’s a big advantage.
The most complicated and advanced type of differential, a torque-vectoring differential uses a collection of sensors and electronics to obtain data from various things (road surface, throttle position, steering system, etc.) to activate electronically actuated clutches and a controller.
Also known as active differentials, they work in the most efficient way which results in a truly dynamic, high-performance driving experience. Torque-vectoring differentials can be found in some high-performance rear-wheel drive and all-wheel drive vehicles.
In a turn, the outside wheel travels farther and faster than the inside one. The differential is a set of gears that transmits engine power to the wheels while allowing them to turn at different speeds on turns.
With front-wheel-drive (FWD), the differential is alongside the transmission inside a housing, and the unit is called a transaxle. With rear-wheel-drive (RWD), the differential is between the rear wheels, connected to the transmission by a driveshaft. All-wheel-drive (AWD) and four-wheel-drive (4WD) vehicles add a center differential or transfer case to distribute power front and rear.
Some hybrid vehicles have “electronic” AWD. These use electric motors to power the rear wheels and turn them faster or slower as needed on turns.
Differential gear, in automotive mechanics, gear arrangement that permits power from the engine to be transmitted to a pair of driving wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven road.
A differential is a gearbox that is found between the drive wheels of your vehicle. If your vehicle has a four-wheel-drive system, then it more than likely has a front and rear differential. A differential works with the transmission to deliver power from the engine to the axle that turns the wheels.
Following are Differential Parts:
There are four common differentials used between vehicles – open, locking, limited-slip and torque-vectoring.
Front-wheel drive vehicles tend to have the engine crankshaft and the gearbox shafts transverse, and with the pinion on the end of the counter-shaft of the gearbox and the differential enclosed in the same housing as the gearbox. There are individual drive-shafts to each wheel.
A differential works with the transmission to deliver power from the engine to the axle that turns the wheels. It also helps your vehicle turn properly. In order for your vehicle to turn, the outside wheels must turn faster than the inside wheels.
If there was no differential on the axle, both wheels would revolve at the same speed. Therefore, they would have a tendency to cover the same distance as each other, which would result in a tendency to go in a straight line. A car with rear-wheel drive would push the front wheels, with their tires skidding helplessly.
The differential is a system of gears that allows different drive wheels (the wheels to which power is delivered from the engine) on the same axle to rotate at different speeds, such as when the car is turning.
The differential sits between the wheels, where the drive shaft connects with the axle. Depending on whether your vehicle is a front-wheel drive, rear-wheel drive, or four-wheel drive, the differential is on the front, rear, or both axles. In addition to differentials, four-wheel-drive cars have a transfer case.
There are four types of car differentials and today, the ASE-certified technicians at Christian Brothers Automotive Independence are going to explain them. Our professionals will break down the different types of car differentials and what to expect from each one.
Differential gear, in automotive mechanics, gear arrangement that permits power from the engine to be transmitted to a pair of driving wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven road.
All vehicles have either a front differential or rear differential as part of the axle assembly. A front-wheel-drive car will have a front differential while a rear-wheel-drive car has a rear differential. If the vehicle has 4-wheel drive then it could have both front and rear differentials.
If new gears are needed the price can be at least $1,500. Going to the worst-case scenario, if the differential is beyond repair, you’ll need the component to be replaced altogether. You can expect a rear differential replacement to cost up to $4,000.
It’s not unusual for automatic transmission or gearbox specialists to also work on differentials, as the components perform a similar task: The transmission or gearbox adapts the engine output to suitable speed and torque to be transferred to the wheels.
When a rear differential fails, it can cause vibration, noise, and fluid leaks that impact a vehicle’s acceleration and driveability. A driver should consult a certified mechanic to deal with a bad rear differential and prevent further damage to the vehicle’s driving systems.
One of the most obvious signs is a loud whirring noise that takes place when your vehicle is decelerating. You also may hear a howl or a whine when you are accelerating. This can be symptomatic of a bad differential.
Symptoms Of a Bad Rear Differential
If there was no differential on the axle, both wheels would revolve at the same speed. Therefore, they would have a tendency to cover the same distance as each other, which would result in a tendency to go in a straight line. A car with rear-wheel drive would push the front wheels, with their tires skidding helplessly.
With front-wheel-drive (FWD), the differential is alongside the transmission inside a housing, and the unit is called a transaxle. With rear-wheel-drive (RWD), the differential is between the rear wheels, connected to the transmission by a driveshaft.
In automobiles and other wheeled vehicles, the differential allows the outer drive wheel to rotate faster than the inner drive wheel during a turn. This is necessary when the vehicle turns, making the wheel that is traveling around the outside of the turning curve roll farther and faster than the other.
A differential is part of the front and/or rear axle assembly. The axle is the central shaft that the wheels on the vehicle rotate around.
These are light repair jobs that will cost between $200 to $400, depending on the make and model of your vehicle. But if you have more extensive damage to your differential that requires it to be dismantled or overhauled, then you are looking at about $400 to $800 in repair costs.
Typically, the differential will start giving strange noises when it goes out, or when the bearing fails. You will hear a whirring noise, whining noise, a growling noise, or howling noise.
A complete rear differential replacement includes replacing the housing, gears, bearings, and seals. The average time it takes a certified mechanic to perform a differential rebuild at a shop is usually three to five hours. A rebuild on a commercial vehicle by someone without prior experience could take much longer.
A rear differential service consists of removing the rear differential cover, cleaning any old fluid from inside the differential case, resealing the cover, and adding clean fluid. After a rear differential fluid change, most vehicles will go 20,000 to 40,000 miles before it’s due again.
The most common sound of a failed differential is a whining noise. This is often due to poor lubrication within the differential, meaning there is a good chance that the differential fluid is leaking. If you spot a reddish fluid under the differential, there is certainly a leak.
