Troubleshoot Engine

Detecting and Fixing a Slipping Clutch: What You Need to Know

slipping_clutch

The most common symptoms of a slipping clutch include a foul burning smell coming from under the car, an engine that accelerates or revs more than it should when the clutch is released, when accelerating hard or when driving up a steep hill.

A slipping clutch is usually caused by wear to the clutch plate and sometimes the flywheel. Clutches will generally wear out over time with normal usage and will usually display certain symptoms before they wear out completely.

7 Common Signs Of A Slipping Clutch

If the clutch is on the way to being worn out, but you can still change gears, then this will result in what we call a slipping clutch.

Usually, a slipping clutch will show up in the way the car performs. You can’t examine the clutch condition easily, so sometimes it can be mistaken for problem elsewhere in the engine such as problems with the fuel injection system.

Here are a few signs of a slipping clutch, and are often signs that you need a new clutch:

  1. Increased Engine Revs Without Acceleration: Engine speeds up, but the car does not accelerate proportionally.
  2. Difficulty Shifting Gears: Hard or uneven gear shifts, particularly noticeable when starting from a stop.
  3. Burning Smell: A noticeable burning odor coming from the clutch area.
  4. Clutch Pedal Feels Soft or Spongy: A noticeable change in the feel of the clutch pedal.
  5. Poor Acceleration: The car struggles to accelerate or feels sluggish.
  6. Momentary Loss of Acceleration: Temporary loss of power when accelerating, especially under load.
  7. Vehicle Moving When Clutch Fully Depressed: The car tries to move even when the clutch pedal is fully pressed.

What causes a clutch to start slipping?

clutch replacement

Pressing the clutch pedal, changing gear and then releasing the pedal must happen in a one fluid movement, and at the right engine speed. If you don’t take care of the  clutch and use it smoothly, it’s going to become unnecessarily damaged and prematurely worn.

Learning to press and release the clutch pedal at the right time and speed takes practice. This is why learner drivers generally put an extra strain on the clutch when learning.

Learners can also be guilty of what is called “riding the clutch”. Riding the clutch is when you leave your foot resting (slightly pressing) on the clutch pedal, after you have changed gear. This will cause the clutch plate to be partially engaged with the rotating flywheel.

Because the clutch is not fully released, it will wear down the friction plates and possibly damage the flywheel. The release bearing will also still be under pressure and spinning, and this can cause it to become damaged and worn over time too. 

riding_the_clutch

A badly worn clutch disc that needed replacement

Of course all clutches will wear out eventually, but certain types of driving conditions will cause it to wear out quicker.

If your daily commute involves sitting in stop-go traffic for an hour and a half each day, then you can be sure that it’s not just your back that’s going to suffer!

Continuously stopping and starting in heavy traffic will wear out your clutch, no matter how good a driver you are. That first instance of contact between the flywheel and clutch disc wears away a small amount of the friction material. Doing it over and over again increases the wear on the disc. 

How to diagnose a slipping clutch?

Here are a few tried and tested ways that you can assess the condition of your clutch. Combine these with the history and age of the car, and you should be able to make an accurate assessment of the clutch condition.

  1. Try to pull away in third gear – If you can manage to pull away from a complete stop in third or fourth gear, without the engine cutting out, then the clutch is slipping. A new clutch should engage fully and the engine would cut out in a higher gear
  2. Assess the “feel” of the clutch – How does the car respond when you press and release the pedal? If it revs or over accelerates this can point to a slipping clutch. If there is a lack of power, this can also mean the flywheel is slipping against the clutch plate.  
  3. Check the position of the clutch – Does the clutch sit a bit higher when you are not pressing it? Does it take less effort to disengage from the engine? Changes to the position and action of the pedal can also point to a worn clutch.
  4. Check the brake fluid level – Most modern clutches are hydraulic and will share it’s fluid with the braking system. As the clutch wears, the release bearing will move inwards, causing a drop in clutch/brake fluid in the top up bottle. Locate the fluid reservoir in the engine bay and see if the fluid level is lower than it should be. (A drop in fluid could also be caused by a leak in the braking system, so you should get this checked out as soon as possible by a qualified mechanic)

What Next – How do you fix a slipping clutch?

It all depends on what’s causing it to slip. If a clutch disc or flywheel is damaged or badly worn, then the only fix is to replace the damaged parts. This usually involves stripping down the clutch and sometimes removing the gearbox.

Sometimes, topping up the fluid in the clutch hydraulic system can help with a slipping clutch. This can sometimes be a temporary fix for clutch slipping.

In some cases, a drop in fluid reduces the pressure in the master cylinder. Most systems share fluid with the brakes. If you check the brake fluid level is low, topping  it up and pumping the clutch pedal a few times can help the situation. Of course, this is assuming there isn’t a problem with the brake system itself, and you would obviously want to get that checked out as soon as possible!

How do you replace a slipping clutch?

If you need to get the clutch replaced, then this is usually a job for a qualified mechanic, or an experienced DIY enthusiast. It’s not something you can do with your car sitting on some jack stands, you’ll need a proper lift or ramp. 

If you are getting it done in a garage, be prepared to pay for the labor, as it usually will be a lot more than the cost of just the parts.

Rather than try to explain it, here’s a video of a clutch replacement in a Ford Mustang.

About the author

The Motor Guy

The Motor Guy is a passionate car enthusiast with a love for troubleshooting and diagnosing all sorts of vehicle problems.

With years of experience in OBD diagnostics, he has become an expert in identifying and solving complex automotive issues.

Through TheMotorGuy.com, he shares his knowledge and expertise with others, providing valuable insights and tips on how to keep your vehicle running smoothly.

Qualifications:
- 12 years experience in the automotive industry
- ASE Master Automobile Technician
- A Series: Automobile and Light Truck Certification, A9 Light Vehicle Diesel Engine Certification
- Bachelor's Degree in Information Systems

2 Comments

Click here to post a comment

  • I recently started noticing a burning smell from my car and difficulty shifting gears. Could these symptoms indicate a problem with my clutch?

  • I’ve been feeling like my car struggles more than it should whenever I’m climbing steep hills or when I try to accelerate quickly. This happens even though the engine seems to rev up. How do I determine if this issue is specifically due to a slipping clutch or if it’s another problem with the engine itself?