FreightViking is reader-supported. We may earn commissions if you buy through our links. Also, as an Amazon Associate we earn from qualifying purchases.

Semi Truck Noises You Shouldn’t Ignore! (12 Common Problems)

One rule before driving your semi truck or any vehicle is to ensure that it has no issues.

Everyone will agree that noises coming from semi-truck should not be left unattended, or it can mean something more serious.

These noises may come from component damage, electrical system problems, worn-out brake pads, transmission issues, faulty alternators, low oil levels, boosts, and fluid leaks.

This article will thoroughly discuss what causes noises on semi-trucks to avoid them immediately.

Semi Truck Just Clicks When Trying to Start

Every time you try to start the semi-truck, it just makes a clicking noise. Did you ever wonder what that clicking sound means?

For some important reason, you’re in a hurry and need to start your semi-truck as soon as possible. Yet, it happens that it just won’t despite the diligent effort.

Well, it could be because of your battery, damage to the electrical system, or an unnoticed problem with the alternator. 

The battery of the semi-truck might be dead, or there could be an issue with the alternator, whose role is to charge the battery. 

The problem could be in the electrical system, such as the starter. It could rapidly turn on and off and create a clicking noise when it doesn’t have much power. 

Semi Truck Making Knocking Noise When Accelerating

There could be a variety of reasons which cause the knocking noise in your semi-truck when accelerating. The goal is to find a solution to whatever problem it is.

It could be because of the lower fuel level than the air percentage. It can also be because of a faulty spark plug, low oil, or low octane levels.

Let’s discuss how the knocking happens. Your semi-truck engine knocks because of the ignition of fuel and air in the cylinder. In return, it produces a knocking noise.

Now, one reason might be due to low fuel. Since there is not much fuel in the cylinder, there happens a problem with the burning time, which later results in detonations.

When some fuel detonates first before other energy, engine knocking happens. It can be even worse when your semi-truck is accelerating.

As stated above, other reasons may also produce the engine knocking noise.

Semi Truck Grinding Noise When Accelerating

The most common reason why your semi-truck produces grinding noise when accelerating is because of a damaged or worn-out wheel bearing. 

One might think it is because of other factors, but you might set the truck in high gear.

A damaged or worn-out wheel bearing may cause noise and lead to other problems and issues in the transmission, wheel hubs, and more parts. 

Aside from that fundamental cause, there are also many other reasons for the grinding sound when accelerating which we will discuss in other subtopics.

An efficient solution to the wheel bearing problem is replacing them. If the same is still fixable, you may do so, but it is best to replace it with a new one.

Semi Truck Grinding Noise When Coasting

Thinking that you could save fuel, you kept coasting while driving your semi-truck. However, you also keep on hearing grinding noises that make you anxious. 

You cannot quickly pinpoint and conclude which causes which. It would be best to consult an expert to determine its legitimate cause.

Yet, possible reasons are either due to engine or transmission issues. 

It may be because of worn-out gear. Worn-out equipment can already cause damage to your transmission system, which can also damage other parts of the truck.

It can manifest quickly using noise production in your semi-truck as you coast.

Semi Truck Grinding Noise When Driving

We include the possible reasons already mentioned above. They can also cause a grinding noise on your semi-truck when driving. 

But let’s also try to look for other reasons. Constant grinding should not be disregarded as it can signify something more serious that might compromise people’s safety. 

We see that there might be a problem with the differentials of your semi-truck.

The latter is a component that allows different speeds for the car’s wheel. DIfferentials work by enabling the wheels and engine to revolve at several rates.

When there is a problem in the differentials of your semi-truck, you will likely hear a grinding noise as you drive. 

Semi Truck Makes a Noise When Turning

The safety of the driver and passengers of your semi-truck is the utmost priority. Thus, you must also check for the causes when your semi-truck makes noise as you turn. 

When you hear a noise while turning, the most probable cause of the sound is because of damage to the CV joint. 

Constant-velocity or CV joints are what connect the transmission to the car wheels. When the same malfunctioned, you probably heard a clicking or banging noise from your truck.

As mentioned above, it can be because of many other reasons. The thing is to resolve it first before you proceed with driving again. 

Semi Truck Squealing Noise

Damaged or worn-out brake pads may cause a squealing noise from your semi-truck

The squealing noise is an indicator that there is already an existing problem with the brake pad material. 

You should expect this to happen if your brake pads are made of cheap, low-quality materials, not to mention that the same is thin.

Brake pads are susceptible to being worn out early, so you must choose good-quality ones to avoid frequent replacement.

Semi Truck Making a Whistling Noise

A whistling sound may indicate that your semi-truck has a boost leak or similar problem. 

The high-pitched sound happens when parts of your truck, like the clamps, leak air. Also, the leak can affect your semi-trucks overall performance.

The key here is to check any signs of oil in your truck’s hoses. Oil must not be present, or else it could mean that there’s already a leak.

Make it a habit to check the clamps, or it could also result in a boost leak. However, preparing a boost leak tool in case of emergencies is best.

Semi Truck Brake Noise

A semi-truck squealing noise might be due to worn-out or loose brake pads.

When the brake pads get low, they start to squeak. It serves as a warning to truck drivers that the pads need to get checked to be replaced.

The noise happens when the wear indicator, a piece of metal, starts to get exposed and grinds with the rotor when the brake pads are already low.

The contact of two metals makes a grinding or squealing that indicates a fair warning that something is wrong with the brake that needs to be addressed at the earliest possible time. 

We could get new brake pads. Do not hesitate and get your semi-truck consulted by experts. 

Semi Truck Air Brake Noise

The sound of compression in the brake system of heavy vehicles such as trucks and semi-trucks sometimes creates a hissing sound. 

The “chh” noise could be caused by air passing through the tubings up to the air tank. This type of noise could be typical, but not all the time. It depends on the kind of noise too.

If the noise produced is a grinding sound, it could also indicate danger. It would be best to stop driving immediately because a worn-out brake pad could cause it. 

Continued use of brake pads makes them looser and looser and eventually worn out.

Semi Truck Brakes Make Noise When Stopping

Again, worn-out brake pads would not function properly. It can also create a sound when stopping.

Your semi truck’s brake pad is already faulty when it creates a different sound as you drive, turn, or even stop. 

The metal brakes are already touching the rotor, which creates an annoying, if not disturbing, sound. 

As mentioned several times in this article, it is your call to have them replaced to avoid further damage. 

Semi Truck Transmission Noise

We’ve been mentioning transmission issues all over this article but let’s divulge deeper into that. 

The noise coming from the transmission could be due to fluid leaks. 

Fluid leaks may sound as simple as it is, but they may still cause huge problems when disregarded. 

The most practical thing is to have an overall glimpse of your semi-truck, including checking under it before driving. 

This way, you can easily see whether there is a leak and other foreseeable problems in your semi-truck that is avoidable.

Once you think you cannot fix the problem, do not delay and immediately contact experts to provide solutions.