Light-Duty Drivetrains Explained
Light-duty trucks use many of the same components as medium and heavy-duty trucks, but they’re often set up differently. One of the primary differences is light-duty trucks are more likely to have different selectable drive modes. For example, a Dodge Ram 3500 pickup is more likely to have a 4-wheel drive-oriented transfer case than a large Peterbilt Semi. In this case, the Dodge would have the same drivetrain in the rear as the Peterbilt, but extra components upfront. 4-wheel drive setups usually include a secondary driveshaft connecting your transfer case and front differential. Depending on the light-duty truck, the front drivetrain components may be even more complex in the case of an independent suspension setup rather than a solid axle.
Symptoms of a Malfunctioning Light-Duty Drivetrain
Drivetrains are quite complex and need to be maintained and repaired on a regular basis. One of the most common problems in light-duty drivetrain setups is a warped or worn yoke. Yokes are essentially metal knuckles that connect different drivetrain components together. If they warp, you’ll likely notice a shuddering when you slow down, and potentially even shaking at high speeds. Other common symptoms of a malfunctioning drivetrain include the inability to shift into 4-wheel drive, an overheating transmission, and clunking sounds when turning.
Heavy-Duty Drivetrains Explained
Heavy-duty drivetrains are less like light-duty drivetrains in the sense that they don’t usually have selectable drive modes. Medium and heavy-duty trucks are generally rear-wheel drive only and have multiple rear axles rather than one. This provides them with more traction in the rear, all the while allowing them to haul significantly more weight. The vast majority of heavy-duty trucks will have two rear axles, and larger trucks may even have three sets. In the case of a three-axle setup, one axle will likely lift off the ground and only make contact when the driver activates that axle. Do keep in mind that for every axle in the rear, a differential is present.
Common Heavy-Duty Drivetrain Problems
One of the most common heavy-duty drivetrain problems is leaking gear oil. Every axle and differential housing on a heavy-duty truck needs to be lubricated at all times. Although this oil doesn’t need to be changed very often, routine inspection is a must, for gear oil leaks are quite common. Gear oil will either leak from your axle seals on your wheel hub, or from your differential plate gasket. In either case, it’s of the utmost importance that you bring your truck in for service. An axle and differential set that isn’t properly lubricated is at risk of snapping or warping.