Truck parts: What you should know about the drivetrain
As written for The Safe Driver.
Commercial trucks of all makes, models, and sizes all rely on drivetrains to transfer energy from the engine to the wheels and make these large, heavy vehicles move. This essential automotive part helps to send power from the engine through the transmission to the drive wheels. Drive wheels can be in the front or rear, or all four of them can receive power from the engine. Read on to find out what truck drivers and fleet managers should know about this vital truck component.
Most Commercial Trucks Are Rear-Wheel Drive
Most commercial trucks are rear-wheel drive, meaning it’s the rear wheels that receive the power from the engine via the drivetrain. The reasoning behind this is simple. Trucks usually have heavier rear axles, and most of the added weight they carry in the form of cargo is distributed further toward the back. As a result, people buying commercial automann parts should note that aftermarket drivetrains will be designed for rear-wheel drive vehicles.
There is a second reason that large, heavy-duty trucks almost always feature rear-wheel drive, and it’s the added maneuverability. Front wheels that aren’t attached to the drivetrain give these large, difficult-to-maneuver vehicles a more forgiving turn radius.
All-wheel drive (AWD) trucks are the exception to the rule, but they are few and far between. Most of them are designed specifically for military applications. They are rarely used in the commercial sector.
Drivetrain Components
Every drivetrain is a little different in terms of design but they all feature the same main components. Those are:
- The transmission transfers power and enables gear-shifting.
The driveshaft connects the transmission to the rear axle, allowing it to provide torque.
The universal joints (U-joints) are found at either end of the driveshaft and allow it to pivot as the vehicle goes over bumps in the road.
The differential is the housing found in the middle of the axle that distributes equal amounts of power to each drive wheel.
The axle shafts are found on either side of the differential and help to deliver power.
Front-wheel drive vehicles also feature constant-velocity (CV) joints designed to allow the axle to move with the vehicle while also turning the wheels. Since most commercial trucks are rear-wheel drive, there’s no need to worry about CV joints.
How RWD Drivetrains Work
The drivetrain’s work starts at the transmission, the part of the truck that controls how much power gets routed from the engine to the wheels. The driveshaft is connected to the transmission and spins rapidly to transfer power to the rear differential. The rear differential distributes that power to the rear axles and from there to the rear wheels. At that point, the truck gets propelled forward or backward down the road.
Signs of Drivetrain Failure
Drivetrains don’t fail out of nowhere. They just about always start to exhibit signs of impending problems before the situation gets dire. Drivers should always be on the lookout for worrisome symptoms such as:
- Fluid leaks from differential
Noticeable vibration
Shifting problems
Unusual noises
If the check engine light accompanies any or all of these signs, that’s even more reason to head to a mechanic or alert the fleet manager.
The Importance of Buying High-Quality Drivetrain Parts
The drivetrain is an essential part of any vehicle, including commercial trucks. When parts need to be replaced, mechanics need to prioritize buying quality brands. Aftermarket parts are often just as suitable as OEM parts, but only if they come from reputable dealers.