Bad Automatic Transmission: Symptoms, Repair Cost, and More

Written by

Mia Bevacqua, ASE Certified Master Automobile Technician

Automotive Subject Matter Expert at CarParts.com

Updated on February 2nd, 2024

Reading Time: 4 minutes
Summary
  • Some symptoms of a bad automatic transmission include abnormal shifting, strange noises, neutralizing, shuddering, an activated check engine light, and dark or contaminated transmission fluid.
  • Driving with a bad transmission may result in your vehicle neutralizing and being unable to move under its own power.
  • Some transmission issues can be fixed with simple in-vehicle repair or a software update. However, transmissions that need to be rebuilt or replaced can cost anywhere between $2,000 and $6,000 to fix.

The transmission is the second most costly part of your car, next to the engine. Rebuilding or replacing the transmission can cost thousands of dollars and have your vehicle out of commission for days or even weeks.

In other words—an internal transmission failure is a real headache. If your car’s automatic transmission is going out, you’ll likely notice one or more symptoms that will alert you that trouble lies ahead.

How to Know When Your Transmission is Going Out

Your car’s transmission—a complex assembly with many internal components—manipulates rotational force from the engine and transfers that force to the drive wheels.

The transmission is the second most costly part of your car, next to the engine.

In a traditional multi-speed automatic transmission, multiple planetary gear sets create the necessary gear ratios to maximize engine output throughout the vehicle’s operating range. Control devices (e.g., clutches and bands) are used to manipulate the planetary gear sets to switch gears.

Hydraulic fluid is the medium that activates the control devices inside of the transmission. When the engine is running, a fluid pump sends pressurized fluid to the various passages inside the transmission’s valve body. From there, a collection of valves inside the valve body direct the fluid to where it needs to go.

There is also a device called a torque converter that’s located between the engine and the transmission. The torque converter acts as a fluid coupling device that takes the place of a clutch in a manual transmission, allowing the vehicle to come to a stop without stalling.

Modern automatic transmissions are governed by a computer, which is often referred to as the transmission control module (TCM). The TCM receives input from various sensors, then uses that data to determine the operation of output devices, such as the solenoids that control shifting and torque converter clutch operation.

In addition to traditional multi-speed automatic transmissions, there are two other common automatic transmission types: continuously variable transmission (CVT), and dual-clutch. Each serves the same purpose as a traditional automatic transmission but operates differently.

CVTs use a belt and set of adjustable pulleys to vary the transmission’s “gear ratio”. Meanwhile, dual-clutch automatic transmissions operate much like a manual transmission except that an automated dual-clutch assembly handles shifting duties.

The Top Automatic Transmission Failure Symptoms

When your car’s automatic transmission starts to fail, you’ll likely notice one or more of the following symptoms:

Abnormal Shifting

One of the most common signs of an internal transmission problem is abnormal shifting. Automatic transmissions often begin to “slip” when one or more of the control devices fail to hold. This slippage results in an increase in engine RPMs without an increase in vehicle speed. Harsh and/or delayed shift engagement can also point to an internal transmission problem. 

Strange Noises

An internal transmission failure that affects the operation of the fluid pump will often result in a whining noise that coincides with engine speed. Other odd sounds you may hear coming from the transmission include growling from worn bearings and grinding from damaged gear sets.

Neutralizing

In some cases, an internal transmission failure will result in the vehicle neutralizing, meaning no power is being sent to the drive wheels. In such a scenario, the engine will run, but the vehicle will not move under its own power.

Shuddering

CVT automatic transmissions will often produce a shuddering sensation when their internal belt starts to slip on the pulleys. Dual-clutch transmissions may also lead to shuddering when there’s a problem with the dual-clutch assembly. Torque converter problems—with either a CVT or traditional automatic—can result in shuddering, as well.

Illuminated Check Engine Light

On modern vehicles, the TCM monitors transmission operation. If the module detects a problem with the transmission or its control circuitry, the device will turn on the check engine light and store a diagnostic trouble code (DTC) in its memory. Some vehicles may also turn on a separate transmission warning light when there’s a problem.

Burnt or Contaminated Transmission Fluid

When a transmission suffers an internal failure, the fluid will often be dark in color and smell burnt. Once the transmission pan is removed, you may also find signs of excessive friction material and/or metal debris in the bottom of the pan.

What Happens When You Drive With a Bad Transmission?

Driving with a bad transmission can eventually leave you stranded if the vehicle begins to neutralize and will no longer move under its own power. What’s more, depending on the problem, a bad transmission can damage other parts of the vehicle. To be on the safe side, it’s a good idea to repair or replace a faulty transmission as soon as possible.

Is a Transmission Expensive to Fix?

Yes, transmissions are generally quite expensive to fix. If your car’s automatic transmission needs to be rebuilt or replaced, you can expect to pay somewhere between $2,000 and $6,000 for a professional to do the job. Of course, the exact cost of the repair will depend on several factors, such as the year, make, and model of your car.

How Do You Fix a Transmission Failure?

Some transmission issues can be fixed with a simple in-vehicle repair or software update. But if the transmission has failed internally, it will either need to be rebuilt (if possible) or replaced. Many dealerships and full-service repair shops no longer rebuilt transmissions. As such, you’ll typically need to visit a dedicated transmission shop to get a rebuild.

Shopping for Replacement Transmission Parts For Your Vehicle

Failing to repair or replace transmission components that have gone bad can have some disastrous consequences for you, your vehicle, and the people around you. On the bright side, you can get a replacement easily thanks to CarParts.com.

You can get your hands on new transmission parts that are compatible with your vehicle without ever leaving your room. Simply visit CarParts.com, and use our vehicle selector to check out the available parts for your specific model year.

We only source our products from the most reliable names in the industry. On top of that, we ship out orders from strategically located distribution centers across the US. This means customers can get their orders in a matter of days.

Get your vehicle back on the road in no time by shopping for transmission parts today!

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.