Symptoms of a Worn Clutch in an Automatic Transmission Car

When we talk about the clutch, we typically think of cars with a manual transmission. However, although some automatic cars do not have this component, many automatic transmissions use internal clutches, meaning they can wear out and fail just like in any other vehicle.

A slightly experienced driver can tell when a clutch isn’t working properly just by listening and paying attention to the feedback transmitted by the engine. If the engine RPMs climb and the noise increases, but the car doesn’t pull forward as it should when stepping on the gas pedal, you most likely have a faulty clutch—whether your car is manual or automatic.

While the clutch on a manual transmission is operated via the clutch pedal, the clutch (or clutches, as dual-clutch gearboxes exist) in an automatic transmission works differently, yet serves the exact same fundamental purpose of connecting or disconnecting the engine from the gearbox.

Can an automatic car’s clutch wear out?

Of course it can. Automatic transmissions contain wear parts, such as bearings, bushings, seals, and friction pads, which are designed to wear down through friction and are essential for the proper operation of the transmission.

Of all the wear components inside an automatic transmission, the clutches are the most susceptible to failure. Each gear in the transmission consists of a clutch pack made up of friction discs, also known as clutch plates, positioned between steel plates. When the vehicle’s transmission control module shifts gears, it uses solenoids to apply hydraulic pressure to the steel plates of each gear, compressing the clutch discs. The discs lock up through friction and drive the gear.

As the vehicle shifts gears over thousands of miles, the clutch discs wear down slightly with each shift as they engage and disengage. The clutches in an automatic transmission eventually fail when they wear down to the point where they can no longer lock up properly and begin slipping against each other. When they slip, they generate heat that accelerates the wear process.

How long does the clutch last in an automatic transmission?

Typically, the clutches in modern automatic transmissions last between 125,000 and 170,000 miles (200,000 and 275,000 kilometers) before they can no longer handle the weight of the vehicle.

However, several factors can shorten the lifespan of the clutch, such as increased vehicle load and excessive engagement and disengagement cycles. Excessive weight puts added strain on the clutch packs, forcing them to work harder, generate more heat, and wear out faster.

Driving in stop-and-go traffic can also reduce the life expectancy of automatic transmission clutches due to frequent engagements and disengagements. Conversely, the clutches in an automatic transmission vehicle driven at steady highway speeds will last significantly longer.

Following the recommended service intervals for transmission fluid and filter changes is crucial to ensuring the longevity of the gearbox. Neglecting these scheduled services can cause the automatic transmission fluid (ATF) to lose its cooling capacity and accumulate debris. This, in turn, can accelerate the rate at which the clutch discs wear down over time.

Therefore, it is essential to service the transmission regularly to maintain the cooling properties of the fluid and prevent debris buildup.

How can I tell if my automatic car’s clutch is failing?

If the automatic transmission clutch is in poor condition, you will notice that the transmission slips when trying to accelerate. Slipping occurs because worn friction surfaces cause the clutch discs to slide against one another instead of locking up properly. This condition is sometimes referred to as a “burnt clutch,” as the heat generated by the worn clutch pack can produce a burning smell.

It is worth noting that the exact same issue can also occur in manual transmissions, where this problem can appear in record time in vehicles driven by people with certain bad habits—such as riding the clutch pedal longer than necessary—or in cars driven by novice drivers.

What does a slipping clutch feel like in an automatic transmission?

When the clutch in an automatic transmission slips, it can make the vehicle feel unresponsive and sluggish.

You may notice that when you step on the gas pedal, the engine revs up, but the vehicle does not accelerate as quickly as it should. This can result in a feeling of reduced power and slower-than-normal acceleration.

Does a burnt clutch affect acceleration?

Acceleration can be directly affected by a failing clutch in an automatic transmission. When the clutch discs wear out, the transmission can slip, causing a loss of acceleration. As a result, when you press the accelerator, the engine RPMs may climb, but the vehicle may not pick up speed at the same rate it used to. Therefore, a bad clutch can significantly impair the vehicle’s ability to accelerate.

Can changing the transmission fluid stop clutch slippage?

Replacing the transmission fluid if it is degraded or low can prevent this issue. However, if the transmission fluid level is proper and the slipping persists, the transmission will likely require a rebuild or replacement.

If you have already exhausted all other options, a non-slip transmission fluid additive may help alleviate the problem temporarily. However, it is important to keep in mind that this is rarely a permanent fix, and a transmission rebuild or replacement may still be necessary in the long run.

What are the symptoms of low transmission fluid?

A low transmission fluid level can be detected by checking the dipstick and seeing that the fluid level is below the mark.

Additionally, signs of low transmission fluid include a discrepancy between engine RPMs and vehicle acceleration when pressing the gas pedal, as well as the transmission failing to engage or slipping out of gear.

How is an automatic transmission problem diagnosed?

There are certain warning signs or symptoms that can help identify a problem with an automatic transmission. These include:

Transmission slipping in and out of gear

When a transmission starts slipping in and out of gear, it indicates underlying trouble and means the gearbox may not last much longer.

This issue can be caused by low hydraulic fluid pressure, a stuck valve body valve, or a faulty pump. It is recommended to have the transmission inspected as soon as possible if this problem arises to prevent further internal wear and higher repair costs.

Clutch slippage

If the engine revs up without matching acceleration when stepping on the gas pedal, it could point to problems with your automatic transmission’s clutch packs. This issue can stem from several factors, such as a low fluid level or worn-out clutch discs.

You may also notice a burning smell when the clutch plates are worn, especially when trying to pull the car out of a demanding situation, such as starting from a dead stop on a steep incline.

Delayed gear engagement

If the vehicle hesitates to engage or shift gears after pressing the accelerator pedal, it may be due to an issue in the transmission valve body or a low transmission fluid level. It can also be caused by debris buildup inside the transmission or in the fluid itself.

Degraded transmission fluid

Old, burnt-smelling transmission fluid, along with debris or metal shavings, can cause severe transmission issues that must be addressed as soon as possible. The degraded fluid may not dissipate heat effectively, and debris can clog fluid passages or lodge between the clutch discs, causing internal damage.

Therefore, it is vital to flush and replace old transmission fluid with fresh ATF to prevent these failures.

How do you test an automatic clutch?

A quick way to evaluate the condition of the clutches in an automatic transmission is to lightly press the brake pedal, shift the transmission into drive, and then apply throttle to see if the transmission clutch can hold against the added resistance of the brakes.

If the transmission slips during this stall test, it is an indication that it is not holding pressure properly and may need a replacement or rebuild soon.

Conclusion

In summary, a faulty clutch in an automatic transmission can be identified by slippage—when the engine RPMs climb without the expected acceleration upon pressing the gas pedal—and by the smell of burnt transmission fluid.

These symptoms occur due to worn clutch friction discs rubbing against each other instead of locking up, generating excess heat that overheats the transmission fluid and produces that unmistakable burning odor.