Tackling Transmission Failures

Under the hood of our cars rests an integral component to making them move —the transmission. 

This system is responsible for transferring power from the engine to the wheels, and it does so through a series of clutches, gears, valves, and computers. Over time, transmission parts can experience wear and tear due to various factors, leading to transmission failure.

Transmission failure can be a costly repair, so it's important to be aware of the warning signs. Some common symptoms of a failing transmission include unusual noises, slipping, grinding, and jerking when engaging and shifting gears.

A failing transmission can lead to various issues ranging from your vehicle making loud noises, behaving erratically on the road, or being undrivable.

So, how do you prevent transmission failure? It all starts with learning the warning signs —and knowing how to respond. Look at the top seven signs that your transmission may fail.

What Is a Transmission?

Before we look at the top seven signs of transmission failure, let's first understand what a transmission is and how it works.

A transmission’s job is to smoothly transfer power from the engine to the wheels through a system of clutches, gears, or pulleys, allowing your vehicle to travel at different speeds while the engine maintains an efficient power range. These gear ratios also ensure your engine works efficiently, lowering engine rpm, reducing wear and tear, and allowing for better gas mileage. While there are several types of transmissions, their function is the same—to make your vehicle move forward and backward powerfully and efficiently.  

An improperly working transmission can be extremely dangerous, as the vehicle could behave unpredictably or lose power on the road.

Caring for your transmission through regular maintenance, good driving habits, and awareness of the signs of transmission failure can help prevent accidents and costly repairs.

7 Signs Your Vehicle's Transmission is Failing

The transmission uses a series of clutches and gears to transfer power from the engine to the wheels. As the gears shift, they may make a slight engagement sound—which is normal. 

If you start hearing a loud, persistent, clunking noise when engaging gears or changing speed, it could be a sign that your engine or transmission mounts are worn or broken. Mounts keep your transmission and engine in place. When the mount doesn’t function, these components start moving around and could make a clunking or banging noise. 

Worn or broken mounts are the most likely cause, but there are other possibilities:

• Your universal or CV joints might be worn and not functioning properly.
• Old or low transmission fluid that is causing heavy friction between gears due to lack of lubrication.
• One of the many springs, bearings, clutches, drums, or gears in your transmission might be dislodged or broken. 
• A faulty sensor might be gathering incorrect information regarding speeds or shifting.

If these clutches or gears become worn or damaged due to various factors, such as age or lack of maintenance, they can start making a clunking sound when they engage and shift. This is usually one of the first signs that something is wrong. Over time, the noise will only get louder as the damage worsens.

2. Burning Smell

A burning smell is never good.

While it doesn't necessarily mean that your transmission is about to fail, it does mean that something bad is likely happening somewhere. The most common culprit is an issue with your transmission fluid. Either you do not have enough transmission fluid, it is leaking, or it is degraded or old.

Transmission fluid lubricates the transmission, making parts in contact move smoothly to reduce friction. Besides lubrication, this fluid also provides hydraulic pressure and absorbs considerable heat from the transmission. Both these functions of transmission fluid are crucial to keeping the transmission temperature under control and working at its best.

Old or degraded transmission fluid loses its lubrication properties. It also gathers impurities within the transmission over time, turning thick and sludge-like, compromising its effectiveness.

An overheating transmission shortens the life of your transmission and can quickly lead to catastrophic failure. Transmissions are among the most expensive components in your vehicle, so replacement can be expensive.  

The simple solution for this problem is to ensure that you have enough transmission fluid and that it’s in good condition. You should also consider getting a transmission flush according to your owner’s manual recommendations. 

If you notice a burning smell, check for leaks and have your vehicle inspected by a transmission specialist as soon as possible.

3. Grinding Gears

In a manual transmission, grinding gears commonly indicate that the clutch assembly is damaged or the synchronizers inside the transmission are worn. Additionally, bad driving habits such as aggressive shifting, shifting at the wrong moment, and not pressing the clutch all the way while shifting will all result in grinding gears. Over time this can seriously damage your transmission.

In an automatic transmission, a grinding noise could indicate a bad bearing, chipped planetary gears, or even a torque converter coming apart. These are all major repair items.  

In an automatic transmission, the torque converter is used to transfer power from the engine using transmission fluid. It is basically a fluid coupler.  Inside the converter is also a clutch disc that is used to engage the converter solidly to the engine during overdrive and what is referred to as lock-up. If this unit fails, the debris from the converter will travel through the transmission causing severe damage, and stalling at stops can result. 

Low transmission fluid can also cause gears to wear and grind since there is insufficient fluid in which to cause them to move together seamlessly. A clogged filter in an automatic transmission can cause issues since a buildup of debris can restrict the amount of transmission fluid getting through, causing the same issues as low transmission fluid. 

4. No Response

Here's an obvious sign that something is wrong: If you notice your transmission isn’t responding quickly—or at all—it's time to take it to a transmission expert immediately.

Various things can cause no response, such as leaking, low transmission fluid, or a defective valve body or solenoid. Sometimes, it can be something as simple as a broken or loose wire to the transmission or an engine or ABS brake problem causing the shifting issue. But regardless of the cause, it's essential to get it checked out before the problem worsens.

5. Leaking Fluids

The transmission system is a closed system. This means when it's working as it should, all the fluids stay inside where they belong. However, if there's a leak, transmission fluid can start to seep out.

Leaks often occur near the rubber hoses, seals, and gaskets. These parts can degrade over time, which can cause transmission fluid to leak.

If you notice any fluids underneath your vehicle, it could be transmission fluid. Take your vehicle to a trained transmission technician so they can diagnose the issue properly and repair the leak.

6. There’s a Warning Light On

There's nothing more concerning than the Check Engine Light (CEL) coming on while you're driving. 

Your engine, transmission, brakes, steering, and suspension have sensors scattered throughout. These sensors are critical in that they feed essential data to the onboard computers. When the readings from these sensors don’t coincide with the usual readings, the CEL illuminates, and performance typically suffers. These sensors pick up on the slightest changes drivers cannot notice. So, never ignore the Check Engine Light. There are hundreds of reasons for the CEL to illuminate. A certified technician can help you pinpoint the problem through proper diagnostics.

However, this isn't the only warning light you should be aware of. If your vehicle has a transmission warning light or a transmission temperature gauge, pay attention. If either is on or blinking, you must immediately bring your vehicle to a technician.  

7. Neutral Is Noisy

Here's a quick way to test how your transmission is doing: Put your vehicle in neutral and let it run. Do you hear any bumping or other noises? Notice any shaking?

If you do, it's likely a sign that something in your transmission's pump or torque converter is failing. There may be a transmission fluid leak, or bearings or transmission pump gears may be worn or damaged, causing them to make noise as they spin. Over time, this continued wear can lead to transmission failure.  If it only makes noise when you are driving in gear, that could be a sign of problems with internal planetary gears, bearings, clutches, or worn or damaged drivetrain parts. Take notice of what conditions cause the noise and make sure your transmission technician gets that information to help them with diagnostics.

Transmission Problems? Visit a Local AAMCO Center!

Transmission problems can quickly spiral into expensive repairs—or even total failure. The best way to avoid transmission issues is to stay on top of maintenance and have your vehicle regularly inspected by a qualified technician.

A trained technician can spot potential transmission problems early on and prevent them from becoming more significant. They can also flush out your old transmission fluid, change the filter, and make any necessary repairs, all of which will help extend the life of your transmission.

If you’re having trouble with your transmission, or are experiencing any of the warning signs listed above, don’t hesitate to take your vehicle to an AAMCO Center near you!