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Common Warning Signs of a Bad Transmission

Common Warning Signs of a Bad Transmission

Transmission problems are quite common but the good news is you can catch the problem before it turns into an expensive repair. Our friend, Marin Huver, from Advanced Transmission Center, is here to teach us how to recognize the classic symptoms of transmission troubles.


Of all the mechanical components that make up your vehicle, the transmission experiences the most wear and tear over a car's lifetime. And a smoothly functioning transmission is just as critical to the functioning of a vehicle as its engine. The transmission's role is to ensure the right amount of power transfers to the wheels to drive at a given speed; it plays a major role in controlling your vehicle. That means that a bad transmission isn't just an inconvenience; it's a safety hazard.

But how do you know when your transmission isn't functioning properly? Below, we will walk through the most common warning signs of a bad transmission, explaining what you will feel, hear, see, and even smell.

What You'll Feel

If you've been driving the same car for a while, you know how your ride is supposed to feel. It's usually pretty smooth, right? Any kind of grinding, jerking, or shaking could be a good indication of transmission trouble. A common symptom in manual transmission vehicles is gear grinding while automatic transmission failure can often be identified by hesitation while shifting gears. The vehicle may also begin shaking or trembling while shifting. Trouble shifting gears may be mechanical, hydraulic, or electric. The best way to diagnose the issue, of course, is to take your car to a mechanic, and quickly; any delay could cause further damage and put you, your passengers, and other drivers at risk.

What You'll Hear

Vehicles have their own unique noises, and just as you become accustomed to the feel of your ride, you also get to know your vehicle's sounds. Transmission failure noises are often characterized by buzzing, humming, clunking, or whining. Typically, automatic transmissions that aren't working properly will make a humming, buzzing, or whining sound. Manual transmissions have been known to emit more severe mechanical noises like clunking. Also, pay attention to the sounds your car is making while in neutral. Quaking or bumping noises in neutral could indicate that you need to add or change the automatic transmission fluid. Ultimately, if your vehicle is making a sound you haven't heard before, it's best to get it checked out.

What You'll Smell

Everyone loves that new car smell, however fleeting it may be. At some point in your car's lifetime, it loses that fresh scent, and you may not notice any smells at all. But one stench to watch out for is a burning odor. When ATF burns, it emits an acrid stench, more like that of burning rubber rather than oil. If you aren't seeing any fluid leakage, the transmission fluid is likely overheating due to clutch debris. This can occur if the fluid has not been flushed from a vehicle with over 100,000 miles under its belt.

What You'll See

The first and most obvious visual cue that may indicate a bad transmission is leaking fluid.

Automatic transmission fluid (ATF) lubricates components to reduce friction and prevent the transmission from overheating. It also acts as a hydraulic fluid to allow gear engagement. Low fluid can lead to overheating, which is the fastest way for a car's transmission to fail. If you spot a pool of red fluid underneath your vehicle, get the leak fixed immediately. However, if the fluid appears dark brown or black, it could be burnt, in which case, a minor repair will not remedy the internal failure that has already occurred. Have your vehicle examined by a professional to diagnose the problem.

Your Check Engine Light is another obvious red flag indicating that something is wrong. If this warning light pops up on your dashboard, do not ignore it. The service light responds to sensors inside the vehicle, detecting slight vibrations that you would not necessarily notice while driving.

The bottom line

Your vehicle has ways of warning you when something is terribly wrong. If you feel, hear, see, or smell any of the signs listed above, take your vehicle to a repair shop right away.


A word from BlackboxMyCar

Thank you Marin, for putting it a way that's so easy to undestand! Identifying certain problems with your car isn’t always the easiest thing to do. But, if you hear, smell or feel something abnormal - it's time to check under the hood. For those who prefer a more hands-on approach, you need more than the ThinkOBD 100 or any basic OBD-II diagnostics tool. If you are looking for one that helps diagnose the Check Engine Light and/or detect transmission problems, we recommend the ThinkDiag. Check out the review video by Budget Nerd!

Check out what other product reviews by our fans, influencers and affiliates on the BlackboxMyCar Community page.

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