What is the Function of Differential Gearbox in Automobile Vehicles?

In a vehicle, the differential provides relative movement to the two rear wheels when the car is taking a turn. The differential gearbox connects the propeller shaft with the rear axle. So, the main function of the differential gearbox is to transmit equal torque to each wheel. In this article, I will discuss the function of a differential gearbox and the advantages of having the gearbox in the differential.


Function of Differential Gearbox

A differential gearbox is a mechanical component typically found in vehicles, and its primary function is to allow for the wheels on the same axle to rotate at different speeds while still receiving power from the engine. In an ABS car, the differential gearbox plays a great role, as the break and the wheels mismatched the different speeds. The differential gearbox helps to provide and store the different speeds of the shafts and saves the life of the axle. Here are the key functions and purposes of a differential gearbox:

Equalizing Wheel Speeds

When a vehicle makes a turn, the outer wheel has to travel a longer distance than the inner wheel. Without a differential, both wheels would be forced to rotate at the same speed, leading to tire scrubbing and potential damage to the drivetrain. The differential allows the wheels to rotate at different speeds, preventing this issue.

Power Distribution

The differential gearbox ensures that power from the engine is distributed to both wheels on the same axle. This enables both wheels to contribute to moving the vehicle forward, improving traction and stability.

Handling and Stability

Differential action also plays a crucial role in vehicle stability and handling. When driving on slippery or uneven surfaces, a differential allows the wheel with better traction to receive more power, which helps maintain control and prevent wheel spin.

Reducing Stress and Wear

By allowing the wheels to turn at different speeds during turns, the differential reduces stress and wear on the tires, axles, and other drivetrain components. This prolongs the lifespan of these parts and contributes to smoother operation.

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Differential gearboxes are especially important for cornering. When a vehicle turns, the outer wheel travels a greater distance than the inner wheel, and the differential allows this speed difference. This is crucial for maintaining control and preventing tire scuffing.

Off-Road Performance

In off-road and four-wheel-drive vehicles, differentials can often be locked or controlled to maximize traction and overcome challenging terrain. This is particularly important in situations where one wheel might lose contact with the ground due to rough terrain.

Functional Parts of Differential Gearbox


A differential gearbox contains several functional parts that work together to achieve its primary function of allowing the wheels on the same axle to rotate at different speeds while still receiving power from the engine. Here are the key functional parts found in a differential gearbox:

  1. Ring Gear: The ring gear is a large, circular gear attached to the differential case. It receives rotational power from the driveshaft and transmits it to the pinion gear.
  2. Pinion Gear: The pinion gear is a smaller gear that meshes with the ring gear. It is connected to the driveshaft and serves to transfer power from the driveshaft to the ring gear.
  3. Differential Case: The differential case is a housing that contains the ring gear and the other differential components. It allows the ring gear and pinion gear to rotate within it.
  4. Spider Gears (Side Gears): Spider gears are small gears that are located inside the differential case and mesh with the side gears. They allow the two wheels on the same axle to rotate at different speeds while still receiving power from the ring gear.
  5. Side Gears (Bevel Gears): The side gears are connected to the axles and mesh with the spider gears. These gears transfer power from the spider gears to the axles, which ultimately drive the wheels.
  6. Axles: The axles are connected to the side gears and extend outward to each wheel. They transmit power from the side gears to the wheels, allowing them to rotate.
  7. Differential Housing: The differential housing encases all the differential components, protecting them and providing structural support within the axle assembly.
  8. Differential Bearings: Bearings are used throughout the differential to reduce friction and allow the various gears and components to rotate smoothly.
  9. Differential Cover: The differential cover is a protective housing that encloses the differential case and its components. It also contains the gear oil or differential fluid, which lubricates and cools the gears.
  10. Spider Gear Shaft: This shaft connects the spider gears and allows them to rotate freely within the differential case.

Advantages of Having a Differential Gearbox

So we know the function of the differential gearbox. Having a differential gearbox can figure the ratio between the moving shafts. So, here are the advantages of having the gearbox in the differential-

  1. Differential gearbox ensures that both wheels contribute to moving the vehicle, improving traction, especially in slippery or uneven road conditions.
  2. Without a differential, the tires on the same axle would be forced to rotate at the same speed, leading to tire scrubbing during a turn.
  3. The gearbox prevents wheel slippage and scuffing, ensuring that the vehicle remains predictable and manageable.
  4. Differentials reduce stress on the drivetrain components by allowing for speed differentiation between the wheels.
  5. The differential gearbox provides the power equally, thus it controls and helps to increase the vehicle stability and power.
  6. Differential gearboxes are versatile and essential for a wide range of vehicles, from everyday passenger cars to trucks, SUVs, and sports cars. They adapt to various driving conditions and offer consistent performance.

Conclusion on Function of Differential Gearbox

In summary, a differential gearbox is a critical component in most vehicles, ensuring that power is distributed effectively to the wheels, improving traction, and allowing for smooth and stable handling, especially during turns. It plays a vital role in extending the life of various drivetrain components and is essential for various driving conditions, from everyday road use to off-road adventures.

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