January 10, 2022

By Tom Probus, BG Automotive Research Specialist

Your vehicle’s engine and transmission are critical components, but without a driveline, you’re not going anywhere. The driveline is often the least understood and most frequently overlooked automotive system. 

First, it helps to understand the differences in the terms driveline, drivetrain, and powertrain. While the three terms are frequently used interchangeably, they are not the same thing. 

Let’s break these terms down:

  • Driveline—Axles, differential, driveshaft, and joints.
  • Drivetrain—The driveline components and the transmission.
  • Powertrain—Everything that powers the vehicle, including the engine, transmission, and driveline components.

What the Driveline Does

The driveline transfers the power or torque from the transmission through the driveshaft which is in turn connected to the differential by the universal joint (U joint). The differential then transfers the power to the axles.

The driveline is made up of four key components: 

Driveshaft—This is the shaft that is connected to the transmission and is the first component in transferring power to the differential, axle shafts and wheels.

Differential—The differential directs power coming from the driveshaft to wheels, allowing them to rotate at different speeds when the vehicle turns. This is important because the wheels must cover different distances as the vehicle turns. Without a differential, one wheel would have to slide. 

Axles—Axle shafts are connected on either side of the differential and out toward each wheel. They rotate independently based on the controls provided by the differential.

U-Joint—Also known as a universal joint. This flexible pivot point is what transmits power and allows for varying angles of the driveshaft.

Why Drivelines Need To Be Serviced

The metal gears in the differential interact in an extreme-pressure environment, creating heat. A lubricant is required for these gears to function properly. Pressure and high heat cause the lubricant to break down. The result is the buildup of gear debris and sludge deposits. These contaminants cause gear damage and eventual component failure.

The BG Driveline Service uses specifically-engineered equipment to remove worn out, contaminated fluid and replaces it with new BG gear oil such as BG Ultra-Guard® Full Synthetic Gear Lubricant or BG Ultra-Guard® LS Full Synthetic Gear Lubricant. This service provides these benefits:

  • Smoother vehicle operation 
  • Extends life of driveline components
  • Prevents unplanned and costly repairs

If your vehicle is experiencing driveline issues, tow your vehicle to your nearest BG Shop. It’s important to keep your driveline components in the best possible environment they can operate in.

BG Shop

by Tom Probus
Automotive Research Specialist, BG Proving Ground
ASE Master Technician
ASE Certified for more than 20 years