Symptoms of a Bad Clutch
Bad clutch symptoms come in different forms, from odd sounds to poor performance to mechanical problems. The source of any of these symptoms can be hard to recognize.
Signs That Your Clutch May Be Going Bad
Problems with the clutch disc itself or its related parts can cause many symptoms.
- Your car may function poorly: it may start out slowly even though the engine is racing. Or it may be hard to get the car into reverse, or into gear at all.
- Noises may indicate a problem: your clutch pedal may make noise, or your transmission may make noise when the car is in neutral. You may hear squealing or growling when you push the pedal or grinding sounds when you shift gears.
- Or the pedal may give you a clue: it may vibrate, chatter, or pulsate, be stiff and hard to push, fall to the floor and stay there, or feel loosely connected or "spongy."
Below, I discuss all these symptoms and tests you can do yourself to diagnose them.
First, a Word About Your Clutch
The clutch assembly contains several components that wear down with use and others that require regular maintenance; so sooner or later can start to give you trouble. Depending on your model, the basic components may include the following:
- the clutch disc itself
- release mechanism (mechanical or hydraulic)
- pressure plate
- pilot bearing
- release (throw-out) bearing
- clutch fork
A clutch can last 50,000 to 100,000 miles (depending on make and model), but clutch service life is greatly affected by stop-and-go city driving, frequent pulling of heavy loads, and "riding the clutch" (resting your foot on the clutch pedal while moving down the road).
And when your clutch fails, it can be difficult to find the cause. But usually, paying attention to tell-tale signs like noises, clutch pedal behavior, and clutch performance will help you locate the likely source.
Using those symptoms, this guide helps you diagnose the most common clutch problems so that you can make an informed decision about your repair. Look for your question below.
I. Diagnosing Clutch Performance Issues
1. My Car Starts Out Slowly But My Engine Races
This is known as clutch slippage. As you release the clutch pedal and accelerate, the vehicle moves slowly while the engine races, usually in high gear.
Slipping is common when a clutch disc is worn out. With the friction material almost worn away, the clutch disc has less surface with which to grip the flywheel and pressure plate, making it hard for the engine to transfer rotating power to the transmission.
Another symptom you'll notice is the clutch releasing sooner, without much pressure on the clutch pedal.
But there are other common causes for a slipping clutch, besides a worn-out disc:
- Clutch linkage in need of adjustment
- Clutch linkage or cable binding (cable housing filled with rust)
- Clutch linkage bent, misaligned, or damaged
- Blocked master cylinder compensation port
- Pressure plate weakened or warped
- Clutch assembly contaminated with oil (because an engine or transmission oil seal is leaking)
- Broken motor mount
NOTE: If you just replaced the clutch (assuming that everything was reinstalled correctly), you may need to give the new clutch time to fully seat. Usually, you need to go easy on the clutch for the first 200 miles.
Is Your Clutch Slipping? A Simple Test
To find out if your clutch is slipping, park in an area with enough space in front of you, away from traffic and people.
- Start the engine and engage the emergency brake.
- Depress the clutch pedal.
- Shift into second or third gear and rev the engine to about 2500 rpm.
- Slowly release the clutch pedal.
As the clutch engages the flywheel and pressure plate, the engine should stall. If the engine doesn't stall, then the clutch is slipping.
Watch the video below.
2. It's Hard to Get Into Reverse
Clutch problems can also prevent you from getting into or out of reverse or third gear.
A stuck gear may indicate problems with the linkage adjustment, a linkage malfunction, or a warped or damaged clutch plate.
3. I Can't Get My Transmission Into Gear
On a hydraulic system, failure to get into gear may indicate problems with the master or slave cylinder or both. Usually, this is accompanied by a change in the way the clutch pedal feels: spongy, loose, or not catching as before.
On a mechanical system, you may be having problems with the clutch disc or pressure plate, release lever, release bearing, shift lever assembly, or control cable.
II. Diagnosing Clutch Noise Issues
1. My Clutch Pedal Makes Noises
With the engine off, you can hear a noise when you depress the clutch pedal or release it, or both. Usually, the noise comes from the clutch release mechanism.
The release device can be hydraulic (as in many modern vehicles) or mechanical. The device is likely to become noisy as lubricant dries out and the mechanism wears down. A cable, rod or connection may begin to scrape, squeal, or clunk.
First, you need to locate the source of the noise with the help of an assistant.
- With the engine off, have your assistant work the clutch pedal.
Open the hood and use a mechanic's stethoscope or a length of rubber hose (a vacuum hose will do) to listen closely along the release mechanism.
2. My Transmission Makes Noises in Neutral
If the car is noisy when the transmission is in neutral, but the noise goes away when you depress the clutch pedal, it's possible the noise is coming from a worn-out input shaft bearing.
3. I Hear Squeals or Growls When I Push the Pedal
As you begin to disengage the clutch—that is, as you start pressing the clutch pedal—you may hear a squealing or chirping noise. This usually points to problems with the release (throw-out) bearing. The release bearing can be worn out, the internal lubricant dried out, or the bearing itself damaged.
Another potential source of trouble is a crankshaft pilot bearing. A pilot bearing that is worn out or damaged can squeal or grind when the clutch pedal reaches the floor. This is because the pilot bearing leaves a gap large enough for the transmission input shaft and clutch disc to vibrate.
So you can tell whether the release bearing or the pilot bearing is the source of the noise. A bad release bearing will start squealing or chirping with a slight depression of the clutch pedal, or before it's fully depressed; a bad pilot bearing will start squealing or grinding as the pedal reaches the floor.
So check the pilot bearing carefully if the clutch release bearing seems in good condition.
4. I Hear Grinding When Shifting Gears
This problem is known as a dragging clutch. It happens when the friction or clutch disc remains engaged or stuck, so the transmission input shaft keeps spinning even when you fully depress the clutch pedal. Since the input shaft is still spinning, trying to shift gears, specially into reverse, will cause them to clash or grind.
- This grinding may point to any number of problems: problems with the pressure plate, throw-out bearing, or release mechanism. On a mechanical release system, the cable may be broken, frozen, overstretched, or in need of adjustment (consult your vehicle repair manual). On a hydraulic-type system, grinding may indicate problems with the clutch master cylinder (low fluid, or air in the system or the internal cylinder mechanism).
- Another possibility you want to look into is the clutch pedal assembly. The pedal may have too much free travel and will need adjustment (consult your vehicle repair manual).
III. Diagnosing Clutch Pedal Issues
1. My Clutch Chatters When I Accelerate
This clutch problem makes the pedal vibrate or, if the problem is severe enough, makes the car jerk during acceleration. The vibration comes from the clutch disc intermittently losing its grip on the flywheel.
Possible causes of vibrating or chattering include:
- Clutch disc lining (friction material) worn out
- Clutch disc lining burnt or contaminated with oil
- Clutch disc glazed
- Clutch disc hub with worn out splines
- Warped pressure plate or flywheel
- Pressure plate diaphragm spring weakened or with broken fingers (bouncing)
- Pressure plate with hot spots
- Pilot bearing worn out or damaged
- Flywheel worn out
Note: Before you go to the trouble of dropping the transmission, make sure to check the engine and transmission motor mounts, because motor mounts can also be the source of chatter. Check the mounts for cracks, damage, or loose bolts.
Also, check that the transmission is correctly aligned with relation to the engine. The transmission clutch housing should be resting fully against the engine; otherwise, this can cause vibration and lead to damage to the clutch disc lining and torsion springs.
A Simple Clutch Chatter Test
- Park in an area with no traffic and no people around the vehicle.
- Engage the emergency brake.
- Start the engine.
- Fully depress the clutch pedal.
- Race the engine to about 2000 rpm.
- Slowly release the clutch pedal.
You should feel the clutch pedal vibrate as the clutch starts to engage the flywheel (engine). If you don't, the clutch disc is not the source of the vibration.
2. My Clutch Pedal Pulsates
A clutch pedal may pulsate because a rotating part is wobbling or vibrating inside the transmission.
The pulsation may be caused by a warped flywheel, or by a release lever that needs adjustment or is damaged.
NOTE: If the pulsation or vibration started after servicing the transmission (the transmission was dropped or just separated from the engine for inspection), it is possible the transmission housing is improperly aligned with the engine.
3. My Clutch Pedal is Hard to Push
A clutch pedal that's hard to push or "stiff" may point to problems with the release mechanism (or the hydraulic system, on modern vehicles). Release mechanism components to check include the cable, linkage, clutch fork, pressure plate, and throw-out bearing.
Check for a part that is in need of lubrication or worn out. Consult your vehicle repair manual for the maintenance service the system needs.
4. My Clutch Pedal Stays on the Floor
Just like a stiff pedal, a clutch pedal that stays on the floor can point to problems with the linkage or release bearing. Either component may bind.
Check that the springs in the linkage are not over-stretched. You may need to adjust the linkage. Also, check that the pedal stop is in place, and, if necessary, inspect the release bearing.
5. My Clutch Pedal Feels Loose
If your clutch pedal feels loose:
- Check the release bearing or fork for damage.
- Check for a failure of the pressure-plate diaphragm spring.
If you have a hydraulic release mechanism, check for:
- Low fluid in the reservoir
- Leaking hose or pipe
- Leaking connection
- Master cylinder, center valve seal fault
- Master cylinder, piston primary seal leak
Consult your vehicle repair manual.
6. My Clutch Pedal Feels Spongy
A spongy clutch pedal (where the resistance fades as you press down on the pedal) usually shows up in a clutch system with a hydraulic release mechanism. Check the hydraulic system for air.
Many Different Sources of Clutch Problems
To sum up, bad clutch problems can be as varied as the parts in the clutch assembly. Problems may come from small components like bushings, pilot bearings, springs, screws, dowels; large parts like the clutch disc, flywheel, pressure plate, or release bearing; or even problems in the drive train or chassis. The symptoms outlined here just touch on the most common problems and some potential sources. Still, this list represents a good start in your diagnostic procedure when facing problems with your clutch.