Onsite Truck & Equipment Repair Blog

5 Indicators Your Heavy-Duty Truck Needs Transmission Repair Immediately


It might be challenging to interpret if a new or odd noise coming from your heavy-duty truck is indeed a problem if you aren't sure what to listen for. Quite often, a change in the truck’s operational behavior or a new noise, especially when shifting gears, can be an indication of transmission problems. Don't risk your road safety by attempting to determine if you need transmission repair. Instead, keep an eye out for these five indicators that your transmission may require repair. 

1. It's hard for you to change gears 

You could need transmission repair if your heavy-duty truck hesitates while changing gears or worse yet, won't change gears at all. If you are experiencing any sort of resistance in changing hears it's important that you get your heavy-duty truck in for transmission maintenance to an expert in order to prevent more harm from being done.


If your heavy-duty truck has a manual transmission, you know that there is a problem if you depress the clutch and move the stick only to discover that your gearbox won't shift into gear. This can be felt either when attempting to shift up and down gears or attempting to shift into first after coming to a complete stop. Heavy-duty trucks with gearbox problems often stall at red lights. Most likely, the issue is low transmission fluid, fluid with the incorrect thickness, or shift cables or clutch linkage that need to be adjusted. 

2. You're slipping gears 

If this happens while driving on the road, it is pretty hazardous. Your heavy-duty truck may change into gear but abruptly shift out of it. An experienced mechanic can solve your transmission problems and safely get you back on the road. 

If there is a problem, you may probably notice one of these impacts, depending on the transmission. If your gearbox is manual, you could hear grinding when you change gears. This is perhaps the result of a clutch that needs to be adjusted or worn out. 

If your heavy-duty truck has an automatic gearbox, you can experience a jolt when it shifts gears. When your heavy-duty truck shifts, you usually don't feel anything, but if you experience a tiny shake or jarring, you probably have an issue. Transmission fluid that is too old or worn might also be at fault. Transmission fluid must be cleaned and replaced, much like engine oil. 

3. Strange noises can be heard even in neutral

If you hear odd sounds, start by topping up fluids that may seem low and, if lubricating the bearings or gears. If this does not immediately solve the issue, It's time to seek the advice of a licensed diesel mechanic. 

Along with unusual noises, you may also notice that your check engine light is on. The check engine light is another sign of something wrong with your heavy-duty truck. If it illuminates, there is a problem. The check engine light might turn on for various reasons, which is one of the reasons why it requires a professional diagnostic service to get down to the root o the problem. 

4. A burning smell 

Your transmission fluid may overheat and burn if the level is too low or if the wrong type of fluid has been used. If you notice any hot or burning odor coming from your heavy-duty truck you should immediately book a service with a heavy-duty truck repair shop. 

Your transmission may be overheating if you smell a strong, unpleasant odor. Burning transmission fluid, which may be the consequence of low transmission fluid due to a leak, is causing this odor. Since the fluid ensures that the many components of your transmission are lubricated and operating as intended, it is crucial to fix this problem as soon as possible. Most significantly, it prevents the burning up of your transmission. 

5. The fluid is low 

The usual solution for low transmission fluid is to top it up with brand-new fluid. If the fluid leak persists, a more severe problem can occur. Don't put off fixing the issue since doing so might end up costing you more money and endangering your transmission. Get the leak looked out as soon as possible. 

You may notice a transmission fluid may leak from your heavy-duty truck if you glance down and see a bright crimson, dark red, or brown liquid under your truck when it’s parked. As previously noted, having low transmission fluid levels is very dangerous for your transmission, and leaking will increase the likelihood of this. 

Final words 

Recognizing problems with your heavy-duty truck may help you keep it in better shape and extend its lifespan. Early detection of a transmission issue will enable you to address it before it worsens. Fortunately, since problems with heavy-duty truck transmissions are often accompanied by a sound or a feeling, they are generally easier to identify and have addressed early on.

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