Is your manual transmission car starting to feel strange when shifting gears? Do you notice the engine RPM is higher than normal before the car moves? A slipping clutch could be the cause, and the situation will only worsen over time.
Knowing how to identify the distinct symptoms of a slipping clutch early on can help you anticipate bigger problems and avoid a breakdown on the road.
What Does a Slipping Clutch Mean?
A clutch is designed to hold a certain amount of engine torque, typically measured in foot-pounds (lb-ft) or newton-meters (Nm). A pressure plate is used to hold the clutch against the flywheel, causing the transmission input shaft and the engine to spin at the same speed.
Clutches are designed with friction material on both sides that grips the metal surfaces of the pressure plate and flywheel. As the clutch wears out, it loses this friction material, much like your brake pads would.
At some point, the clutch can no longer hold the same torque as before. When the engine torque exceeds the maximum torque a clutch can hold, it begins to slip intermittently under higher engine loads.
Instead of gripping the flywheel and pressure plate, a worn clutch will allow the engine to spin freely, even when the clutch pedal is fully released. This phenomenon is often more noticeable in an intermediate gear like third or fourth and gradually worsens over time until the clutch is replaced.
In extreme cases, a worn clutch can leave you stranded, as the vehicle will be unable to transfer engine power to the ground.
This condition is often seen in vehicles that frequently drive in heavy traffic, cars with newer drivers, high-performance vehicles that are driven hard, and cars with upgraded engines producing well beyond their factory power level.
If any of these conditions apply to you, don’t be surprised if you experience clutch slipping issues.
The Top 5 Symptoms of a Slipping Clutch
It’s important to notice a slipping clutch before it causes serious problems for you or your vehicle. You wouldn’t want the engine to disengage from the drive wheels while you’re driving at high speed. This could potentially cause an accident.
So, try to recognize the symptoms of this problem so you can adjust your driving habits and address the issue. Here are five common ways to tell if the clutch is slipping.
1) RPM Increases, But Not Speed
A simple way to check if your clutch is slipping is to take note of the engine RPM. If you press the accelerator pedal to speed up and your engine RPM increases faster than normal while your driving speed doesn’t increase as it should, you likely have a slipping clutch.
For example, you’re driving on the highway and decide to pass a slower vehicle. When you try to accelerate, the engine RPM increases and your engine makes more noise, but your car doesn’t go any faster. A slipping clutch is usually more obvious in higher gears when you try to accelerate.
2) Burning Smell
When the clutch slips, a burning smell emanates from the front of the car. This is due to the excess heat generated by the constant disengagement of the engine and the slipping of the clutch.
The more the clutch slips, the worse the burning smell will become. You don’t want to drive with this smell in the cabin as it will make you nauseous. The more the clutch slips, the worse the condition will get.
3) Poor Engine Performance
The ultimate test occurs when you’re pulling a heavy load in or behind your vehicle. Normally, this would require the engine to send a lot of power to the drive wheels.
But if your clutch is slipping, the engine won’t be able to deliver that power. You’ll then have almost no acceleration due to this lack of engine power. You can reduce the load you’re pulling to increase power somewhat, but this won’t be a permanent solution.
4) Clutch Pedal Height Difference
When driving your vehicle, you should get used to the height of the clutch pedal relative to the floor. When you press the pedal and remove your foot, the pedal should always return to the same height as before.
If you notice the height changing, whether the pedal is too high or too low, then there’s a problem with the clutch. In most cases, this is due to the clutch slipping.
You can try adjusting the clutch pedal to see if it helps, as it’s much cheaper and easier than dropping the transmission to replace the clutch.
5) Quick Disengagement
The most frequent symptom of a slipping clutch is quick disengagement between the engine and the drive wheels. When the clutch is normal, you need to press the pedal about 1 to 2 inches before the engine disengages.
However, with a slipping clutch, the engine disengages when you lightly press the clutch pedal less than an inch. Sometimes, simply resting your foot on the pedal is enough for the engine to disengage.
How to Fix a Slipping Clutch?
There is only one solution to fix a slipping clutch: replacing the clutch.
Sometimes, a leaking rear main seal can cause a good clutch to slip (as the clutch can be lubricated with engine oil), but usually, you’ll just replace the clutch while you’re at it; the mechanic has to drop the transmission anyway to replace the rear main seal, and the cost of parts for a clutch job isn’t very high.
You’ll also need to consider resurfacing or replacing the flywheel and pressure plate, as these parts can degrade with use. If the clutch is worn down to the rivets, there’s a good chance that the excessive heat and metal-on-metal contact have damaged the flywheel and require replacement.
What Causes a Clutch to Slip?
Several factors can cause signs of slipping in your clutch, including driving style and shifting habits. Here are the most common causes:
Worn Clutch Disc
Over time, the friction material on the clutch disc can wear out. This reduces the disc’s ability to grip the flywheel and pressure plate, allowing it to slip when torque is applied through the transmission.
Riding the Clutch
While driving, resting your foot on the clutch pedal puts constant pressure on the clutch. This can cause the clutch to overheat and slip. It’s better to press the clutch all the way down when shifting gears, then release it completely.
Weak Clutch Springs
The clutch disc is compressed between the pressure plate and flywheel by springs. If these springs weaken or break, they won’t exert enough force to prevent slipping.
Starting from a Stop
Quickly releasing the clutch and trying to accelerate aggressively from a stop puts significant stress on the clutch components. This can lead to premature wear and slipping. Of course, burnouts can be fun, but they have consequences.
Low Clutch Fluid Level
Clutches use hydraulic fluid to engage and disengage. If the fluid level is low, the pressure plate may not fully engage with the clutch disc.
Oil Contamination
The presence of oil or grease on the clutch disc can prevent it from gripping properly. A leak at the rear main seal can cause the clutch to be contaminated with oil.
Overheating
Excessive heat buildup, due to heavy loads or riding the clutch, can glaze the clutch disc material and reduce grip. This is commonly referred to as clutch degradation.
Poor Shifting Habits
Not fully depressing the clutch when shifting, shifting into the wrong gear, or releasing the clutch too quickly can cause the clutch to slip as it tries to match the engine and transmission speeds.
Incorrect Downshifting
When downshifting, the engine RPM should be increased to match the lower gear ratio before releasing the clutch. If the clutch is released before the engine RPM increases, the clutch will slip.
Towing or Carrying Heavy Loads
Using the clutch to start from a stop with a heavy load in the vehicle can lead to overheating and slipping over time. The load puts extra strain on the clutch.
Preventing Future Clutch Slippage
To prevent the clutch from slipping on the road, start by regularly checking the clutch fluid. A level that’s too low can cause slipping, so make sure to top it up with the fluid specified by the manufacturer.
Drive smoothly. Avoid sudden starts or reckless gear changes that can prematurely wear out the clutch. Instead, be gentle with the pedal and perform deliberate gear shifts.
Also, ensure your vehicle is maintained. Have a mechanic inspect the clutch system during routine visits. Early detection of any issues can prevent slipping.
When the time comes, invest in a quality replacement clutch rather than opting for the cheapest option. A robust replacement kit will offer better grip and longevity.
FAQ
Can the Clutch Slip in an Automatic Transmission?
Although automatic transmissions aren’t equipped with a manual clutch, they can still experience slipping issues similar to manual vehicles. Instead of a clutch, automatic transmissions use a torque converter and transmission fluid pressure to shift gears. Issues such as low fluid levels or a faulty torque converter can therefore cause gear slipping.
Just like inspecting the clutch on a manual transmission, it’s important to regularly check the transmission fluid and promptly address any slipping issues on an automatic. With proper maintenance and care, slipping can be avoided in both types of transmission.
Slipping or Riding the Clutch: What’s the Difference?
When you experience clutch slipping, it means the clutch isn’t properly transferring engine power to the transmission. The engine then spins faster than it should, while the car doesn’t go any faster. You’ll typically notice an increase in engine RPM without a corresponding increase in speed, a nauseating burning smell, or a feeling of disconnection between the accelerator pedal and acceleration.
On the other hand, riding the clutch is a bad driving habit that involves constantly keeping your foot on the clutch pedal, even when it’s not necessary. This can lead to faster clutch wear, which can contribute to slipping in the long term. Avoid riding the clutch by releasing the pedal between gear shifts or when you’re not actively using it to preserve the clutch’s integrity.
Why Is My Brand New Clutch Slipping at High RPM?
There are several reasons why your new clutch might be slipping at high RPM. First, the clutch may not have been broken in sufficiently yet. It’s important to allow your new clutch time to wear in properly, which may require 500 to 1,000 miles of easy driving. Avoid aggressive acceleration and high RPMs during this period.
Faulty installation could also be the cause of the problem. In some cases, improper alignment or incorrect torque settings can lead to excessive wear or poor clutch performance.