When it comes to keeping your heavy-duty truck on the road, axles play a significant role in the drivetrain. They keep your truck's wheels turning, maintain proper spacing, and shoulder some of the load's weight. But even class 8 semi-truck axles have their limits, which is why taking care of them is essential for a smooth ride. In this blog post, we’ll be covering what causes axle failure, requirements for proper loading, the signs of a bad axle, and everything you need to know about truck axle replacements.
What Causes an Axle to Go Bad?
You know how it goes — if you don’t take care of something, it’ll go bad, and axles are no exception. There are several reasons why an axle can snap, ranging from hitting potholes to poor maintenance. However, the biggest players in truck axle problems are overloading and improper weight distribution.
Overloading your heavy-duty truck places immense pressure on the axles. This excess load can lead to a series of unfortunate events. First, there's the dreaded "pitting." As the case-hardened metal of the bearing race fatigues, it starts developing pits and flakes away from the softer base metal, resulting in spalling in the bearing rollers and races.
Overloading also creates excess pressure between gear teeth, causing deterioration in the metal. And if that weren't enough, it can even force the axle shafts to bend and wobble, which are movements they weren't designed to handle.
How Many Pounds Can a Semi-Truck Carry?
Keeping overloading and improper weight distrubtion in mind, let's talk about weight limits. When it comes to semi-trucks and their loaded trailers, they must not exceed a collective weight of 80,000 pounds. This includes the overall curb weight of each semi-truck, and the dedicated weight to haul your freight will vary depending on the weight of your truck and trailer combo when empty.
For semi-trucks running a tandem axle or 6x4 configuration, they can typically hold no more than 0,000 pounds on the steer axle (front axle) and 36,000 pounds on the tandem drives. On the other hand, semi-trucks running a single axle or 6x2 configuration can typically hold 20,000 pounds or less on the drive axle (rear truck axle). So, be mindful of those weight limits and keep your axles protected!
What Are Signs of a Bad Axle?
Working on a contract? Be mindful of these red flags that will tell you if something’s up with your axles.
#1 - Odd Noises While Driving
Hear that loud clunk when you shift gears or a mysterious clicking noise when turning? Those aren’t noises that your axles should be making. Odd noises like these could be your axle's cry for help, telling you it's time for some tender loving care.
#2 - Vibrations While Accelerating, Decelerating, or Turning
Feeling some unwelcome vibrations during your drive? A bent axle might be the cause, leading to vibrations accompanied by odd rumbling sounds from beneath your heavy-duty truck. Keep an eye out for peculiar tire wobbling or slow steering, accelerating, and decelerating, as these too can signal axle issues.
#3 - Oil Leaks
Leaky axles are a telltale sign that you need to get your axle fixed. If you spot liquid pooling up underneath your axle housing or spraying across your wheel ends, it's a clear sign that you're leaking either gear oil or axle grease. That's a signal your axle needs some professional attention.
How Long Can You Drive With a Bad Axle?
The length of time you can drive on a bad axle depends on the circumstances. If you’re driving with heavy cargo in your semi-trailer or hitting every bump on the road, chances are you won’t even reach a mile.
The best course of action is to call a mobile or truck roadside assistance repair shop near your location. Make sure they’re able to repair your axle on the spot, or else you’ll need to pay extra for a tow.
Are Axles Easy to Replace?
Now, let's talk about replacing axles. It's not exactly a walk in the park, and the complexity of the task depends on the type of axle and the make and model of your heavy-duty truck. Replacing a tandem axle can be particularly tricky due to the involvement of the intricate differential assembly.
As for the cost of axle replacement, it varies depending on various factors. The price range can be anywhere from $600 or more, depending on the extent of the damage, the quality and manufacturer of the axle, labor rates, and more. It's best to consult a reputable heavy-duty truck axle repair shop to get an accurate estimate before you bite the bullet.
And there you have it: the common signs that indicate your heavy-duty truck may be in need of some axle repair. Keeping a keen eye out for odd noises, vibrations while driving, and oil leaks, and promptly addressing any of these issues will keep your heavy-duty truck cruising smoothly on the open road.
Don't let those axle problems slow you down! If it’s too late to prevent axle failure, seek expert assistance from a trusted and reputable heavy-duty truck repair shop in your area.