Clutch plate: what it does, how it wears and when to replace it

The clutch plate (or clutch disc) is the friction disc between the flywheel and the pressure plate that passes engine power to a manual gearbox, and it is built to wear. A worn clutch plate slips under load, bites high and can smell burnt. It is almost always replaced as a kit with the pressure plate and release bearing.

That last point matters more than most guides admit. Getting to the clutch plate means taking the gearbox out, and that labour is the same whether one part goes back in or three. So the real question is rarely “is my clutch plate worn?” but “what exactly is wrong, and what should be replaced in one go so I do not pay for the same job twice?” At ATR Transmissies in Montfoort we answer that with a test drive and a proper check before anything comes apart.

What is a clutch plate and where does it sit?

The clutch plate is the middle layer of the clutch in a car with a manual gearbox. Between the engine and the gearbox sits a clutch assembly made of three main parts, from front to back:

1. The flywheel, bolted to the engine’s crankshaft.
2. The clutch plate, a disc lined with friction material on both sides.
3. The pressure plate, bolted to the flywheel. Its diaphragm spring clamps the clutch plate against the flywheel.

While that clamping force is on, the engine and the gearbox turn as one. The clutch plate itself is not bolted to anything. Its centre hub slides onto the splines of the gearbox input shaft and can move a few millimetres along it. That small freedom is what lets the plate come free the moment you press the pedal. The release bearing (also called the thrust bearing) does that job by pushing on the fingers of the diaphragm spring.

What a clutch plate is made of

A clutch plate looks simple, but it has three parts that each fail in their own way:

• Friction linings. A ring of friction material on each face, riveted or bonded to a springy carrier plate. Small cushion segments between the linings make the clutch bite progressively instead of grabbing.
• The hub. The centre section with internal splines that slides over the gearbox input shaft. The splines must slide freely. If they bind, the clutch no longer releases fully and gears become hard to select.
• Torsional damper springs. The coil springs arranged around the hub. According to clutch maker LuK (Schaeffler), the clutch disc’s job besides transmitting torque is to stop torsional engine vibrations reaching the drivetrain, and most LuK discs use six torsion springs for that. Broken or loose damper springs cause rattling and vibration at low engine speed.

How the clutch plate engages and disengages

When you press the clutch pedal, the release bearing pushes the diaphragm spring inwards. The clamping force disappears, the clutch plate spins free between flywheel and pressure plate, and the engine keeps running without driving the gearbox. You can change gear.

When you let the pedal up, the clamping force builds again. During that short travel the clutch plate slips on purpose: it rubs away the speed difference between engine and gearbox. That controlled slip is normal and necessary, and it is exactly where the friction material is used up. Pulling away on a hill, towing a caravan or launching with lots of throttle costs far more lining than a gentle start on a flat road.

What kills a clutch plate? Four ways it wears out

A clutch plate rarely just “reaches its mileage”. In our workshop we see four different patterns, and only the first one has much to do with distance driven.

• Worn-thin friction material. The normal case. The lining gets thinner until the rivets are close to the surface. The biting point moves up the pedal and the clutch starts to slip under load.
• Glazing. Overheating turns the lining surface smooth and hard. Typical causes are long periods of slipping the clutch, hard launches and resting your foot on the pedal while driving. A glazed plate can still look thick and slip anyway, so lining thickness alone tells you little.
• Oil contamination. A leaking crankshaft oil seal behind the flywheel or a leaking gearbox input shaft seal puts oil on the plate. Oil on friction material means slipping or juddering, and it does not go away. The Borg & Beck clutch fault chart describes an oil-contaminated driven plate as “progressing through clutch drag, judder and finally slip”, with the remedy to eliminate the oil leak and renew the clutch components. If the leaking seal is not fixed at the same time, the new plate is ruined within a short time.
• Mechanical damage. Broken damper springs, loose rivets or a warped carrier plate. Usually the result of overload: more torque than the clutch was built for (for example after engine tuning without an uprated clutch), or dropping the clutch roughly time after time.

Signs of a worn clutch plate

These are the complaints that point to the clutch plate, roughly in order of how clearly they point there:

• Slipping under load. In a higher gear, uphill or with a full car, the revs rise but the car does not speed up to match. You press the throttle, the rev counter jumps and the car responds late. This is the clearest sign the plate has lost its grip.
• A burning smell. A sharp, slightly chemical smell after a steep ramp, a hill start or a long traffic jam. That is overheated friction material.
• A high biting point. The clutch only engages near the very top of the pedal travel. Not a fault in itself, but a hint that the lining is getting thin.
• Judder or shaking when pulling away. A jerky take-up, especially when you pull away gently. This points to an uneven or contaminated friction surface or to the damper springs. Shaking can also have completely different causes, which we list in our guide to a car that shakes or stutters.
• Rattling at idle or low revs. Can come from broken damper springs in the plate, but a worn dual mass flywheel makes very similar noises.

Want to be sure it really is clutch slip and not something else in the drivetrain? Find out what your symptom could mean in our article on a slipping clutch, which explains a simple check and the faults that feel the same.

Is it really the clutch plate?

Slipping under load in a manual car almost always means the clutch plate. Other symptoms are less clear-cut. Judder and vibration can also come from the flywheel, worn engine or gearbox mounts, or the driveshafts. Difficulty selecting gears with the pedal fully down usually points to the release system (cable, slave cylinder or concentric slave cylinder) rather than a worn plate. That is why we test drive the car and read out the control units before we advise anything. Replacing a clutch to cure a driveshaft vibration is an expensive way to learn nothing.

Can you drive with a worn clutch plate?

You can drive with a slightly worn clutch plate for a while, but not with one that slips. A slipping clutch overheats quickly, glazes further and can damage the flywheel and pressure plate surfaces, which turns a clutch kit into a bigger job. Slip also tends to show up exactly when you need power: overtaking, joining a motorway, pulling away uphill. Once the revs flare under load, plan the repair rather than waiting for the clutch to give up completely.

Why a clutch plate is replaced as a kit, not on its own

Technically you can replace only the clutch plate. In practice it is almost never the sensible choice, for one simple reason: most of the work is labour, not the part. The gearbox has to come out to reach the plate, and that costs the same whether you replace one part or three.

That is why we fit a clutch kit as standard: clutch plate, pressure plate and release bearing together. The three parts are matched and wear together. Putting a new plate against an old, bedded-in pressure plate gives an unpredictable biting point and often a new complaint soon after, with the same gearbox removal around it. More on those two partner parts in our article on the release bearing and pressure plate.

While the gearbox is out, we also check the parts that cause repeat failures:

• the crankshaft oil seal and the gearbox input shaft seal (the usual source of oil on the plate);
• the release system: cable, slave cylinder or concentric slave cylinder;
• the input shaft splines and the spigot or pilot bearing where fitted;
• the flywheel surface and, on many modern cars, the dual mass flywheel.

The dual mass flywheel question

Many modern diesel and petrol cars have a dual mass flywheel instead of a solid one. It has its own springs and bearing and it wears too. If it has excessive play or runs unevenly, it makes sense to replace it during the same job: it is in plain sight and the gearbox is already out. If it is within spec, there is no reason to replace it just because. Measuring decides, not habit. Read more in our article on the dual mass flywheel.

Clutch plates in DSG, dual clutch and automatic gearboxes

Everything above applies to a manual gearbox: one dry clutch plate, worked by your foot. A dual clutch gearbox (DCT, such as the Volkswagen Group’s DSG) is a different story. It has two clutches, one for the odd gears and one for the even gears, and a control unit operates them, not you. On the DSG, that happens through the mechatronic unit.

There are two versions:

• A dry dual clutch uses two dry plates that look much like a manual clutch plate. The seven-speed DQ200 DSG, for example, uses two single-plate dry clutches. Because every gear change runs through these plates, they slip far more often than a manual clutch.
• A wet dual clutch uses multi-plate clutch packs that run in oil, as in the six-speed DQ250 DSG. Wet clutches handle more torque and heat but depend on clean oil that is changed on time.

In both cases “replacing the clutch plate” is a very different job from a manual car. It means fitting a complete clutch unit with special tools and then teaching the control unit the new clutch with an adaptation (basic setting) procedure. See our articles on the dual clutch gearbox (DCT) and, for Volkswagen Group cars, on DSG clutch replacement.

A conventional automatic with a torque converter has no clutch plate in this sense: it transmits power through fluid. It does have a lock-up clutch inside the converter that locks the engine side to the gearbox side at cruising speed, and that clutch can also slip or wear.

What decides the cost of a clutch plate replacement

There is no single price for a clutch plate replacement, and the plate itself is usually the cheapest part of the bill. What you pay depends mainly on:

• Labour. On some cars the gearbox comes out quickly. On others the subframe or part of the front axle has to be dropped first.
• What else is replaced. Almost always the full kit, often the flywheel too, plus any leaking seals or a worn slave cylinder.
• The type of clutch. A dry manual clutch, a dry DSG clutch and a wet clutch pack each need different tools and different adaptation work afterwards.

Our article on clutch replacement cost explains how those factors add up. For your own car, contact us for a price indication based on your registration number and complaint.

How ATR deals with a clutch complaint

Our view is simple: diagnose first, then replace only what is needed, and replace it once. In practice that means:

1. You book your car in with the registration number, the complaint and any warning lights or fault codes.
2. We do a basic diagnosis with a test drive and a read-out of the control units, so we know whether it is the clutch plate, the flywheel, the release system or something else in the drivetrain.
3. You decide. Only after the diagnosis do you get our advice and decide what happens. Once the gearbox is out we check the seals and the flywheel, so you know why the clutch wore out and the new one does not suffer the same fate.

We work on manual gearboxes, dual clutch gearboxes and automatics every day, so if the problem turns out to be deeper than the clutch, we can repair the gearbox as well.

Book your car in and we will tell you honestly what your clutch needs.

For garages

Do you run a garage and have a car with a clutch or gearbox complaint you cannot pin down? With ATR Remote we can help with diagnosis at a distance.

Frequently asked questions about clutch plates

What does a clutch plate do?

A clutch plate connects and disconnects the engine and the manual gearbox. Clamped between flywheel and pressure plate, it passes engine torque to the gearbox. When you press the pedal it is released, so you can change gear or stop without stalling. Its damper springs also absorb engine vibrations.

What are the signs of a bad clutch plate?

The clearest sign is slipping: the revs rise under load but the car does not accelerate to match. Other signs are a burning smell after hill starts or traffic, a biting point right at the top of the pedal, judder when pulling away and rattling at low revs from broken damper springs.

What kills a clutch plate?

Heat and contamination kill clutch plates faster than mileage. Long slipping, hard launches, towing and riding the clutch overheat and glaze the lining. An oil leak from the crankshaft or input shaft seal soaks it. Extra engine torque without an uprated clutch overloads the plate and its springs.

Can a clutch plate be repaired?

On a modern car, no. A worn clutch plate is replaced, and sensibly as a kit with the pressure plate and release bearing. What you can often repair is the cause: a leaking seal, a faulty slave cylinder or a release system that does not free the clutch fully.

Can I drive with a damaged clutch plate?

Only briefly and gently. A plate that slips overheats quickly and can damage the flywheel and pressure plate, which makes the repair bigger. Slip also appears when you need power most, such as overtaking. Once the revs flare under load, have the clutch checked.

Is replacing a clutch a big job?

Yes. On most cars the gearbox has to be removed to reach the clutch, and on some cars the subframe or parts of the front axle must come out first. That labour is the main reason to replace the clutch plate, pressure plate and release bearing together in one go.

How long does a clutch plate last?

It varies enormously with driving style and use. Lots of city traffic, towing, hilly routes or more torque than standard shorten its life considerably, while calm motorway driving keeps it going for a long time. A fixed mileage figure tells you very little about your own clutch.

Why does a new clutch slip again?

Usually because of oil. If a leaking crankshaft or input shaft seal was not replaced last time, the new friction material gets contaminated again. Other causes are an old pressure plate left in place, a release system that does not let the clutch engage fully, or parts that do not suit the engine’s torque.

Does a DSG have clutch plates?

Yes, but two of them, and they work differently. A dry DSG such as the DQ200 has two dry plates, a wet DSG such as the DQ250 has multi-plate packs in oil. Replacing them needs special tools and an adaptation procedure afterwards.

Not sure whether it is your clutch plate?

A slipping or juddering clutch rarely fixes itself, but it is also not automatically a clutch kit. Let us check it first. Book your car in at ATR Transmissies in Montfoort and you will know what your car needs before you decide anything.