To know what the heck a differential IS, we must first explore what the heck a differential IS NOT. A differential is not:
So…what the heck is it, then?
A differential is a set of gears that transfers the engine’s power to the wheels, allowing each wheel to rotate at a different speed.
Vehicles are either front-wheel, rear-wheel, or four-wheel drive. That means that the engine’s power is transferred to either the front, rear, or all 4 wheels to move the vehicle. Because not every road is a straight line, vehicles need to be able to make turns. When they make turns, each wheel has a different distance/speed to travel. The differential allows for that to happen without damaging the wheels or the drivetrain.
There are different types of differentials, but I’m only going to address the simplest type: the open differential.
The open differential consists of several gears:
If the vehicle has front-wheel drive, the differential is located between the 2 front wheels, and is usually housed with the transmission. The transmission lubricant also lubricates the differential in this setup.
If the vehicle has rear-wheel drive, the differential is located between the 2 rear wheels, and usually has its own housing and oil. The differential oil needs to be changed every 30-50,000 miles.
If the vehicle has 4-wheel drive, there are 3 differentials—one in the front, one in the back, and a central one located on the drive shaft. The central differential is normally referred to as the transfer case.
If you have about 8 minutes to spare and want to see the basic mechanics of a differential in action, check out this video I found on Wikipedia.
Some common problems with differentials are:
All of those things can lead to failure, which can damage the wheels and drivetrain, and leave you stranded. If you see a leak from the differential area or hear any strange noises, it is best to take your vehicle to your local, friendly mechanic.
So, there you have it. Now you know what a differential is NOT, what it IS, and how it works. Did you get the solution to the math problem at the beginning? No? It’s a slice of apple pie.
Tell me what other automotive parts baffle you. I’ll tell you what the heck they are!