What is the clutch? What problems can it have?

Your vehicle is an extremely complex machine equipped with a myriad of precision mechanical components that function together at high speeds and temperatures. We examine one of these components, the clutch, and discuss its function and common equipment failures.

The clutch is an indispensable mechanical assembly that transfers power from the engine to the drive wheels of a vehicle. Nearly every automobile you see on the road has a clutch of some kind. Even automatic cars have clutches, though these systems are generally of a different, more complex design than those found in a manual transmission. To understand common problems associated with a clutch assembly, you must first understand its components, their purpose, and how they function together.


Clutch basics

Your engine is not directly connected to the drive wheels of your car. If it were, your car could not function, and would likely sustain damage upon starting. Yo”éuipped with a series of gears within the transmission, each of which, when engaged, transfers the power of your engine to the drive wheels at different gear ratios. This allows your car to output extremely high torque at low speeds in low gears, while still maintaining a high top speed in higher gears. The transmission of your vehicle is connected to the engine via the clutch, which is essentially a pressure-mounted friction plate, and functions similarly to disc brakes. When engaged, the pressure plate brings the clutch in contact with the flywheel. This allows the clutch to accelerate to the rotational speed of the flywheel, transferring this power to your car’s drive wheels without the sudden application of the engine’s full torque.

Disengaging the clutch

In a manual transmission, when you depress the clutch pedal, the clutch assembly pushes the friction-material-lined clutch disc away from the flywheel, disconnecting the engine power from your drive wheels, essentially placing the vehicle in a temporary neutral gear. This loss of power allows the vehicle to be adjusted to a new gear, before re-engaging the clutch and reconnecting engine power to the drive wheels.clutch

Without the clutch, attempting to shift a car into a new gear would likely result in the sudden application of overwhelming power at a new gear ratio (assuming the gear could be shifted at all), which would cause the engine to stall and probably damage your car in the process.

Common clutch issues

The clutch is a very complex assembly that functions in some truly adverse conditions. Like disc brakes, the clutch will invariably require replacement at some point during your vehicle’s life, as the friction material lining the disc is designed to wear away in order to allow smooth engine power transfer.

This most commonly manifests as ‘clutch slipping’, when the material has nearly or completely worn away, resulting in a loss of engine power. Clutch slipping can also occur even in relatively new clutches, when oil or other fluids from a leak in the engine contaminate the friction lining of the clutch disc. If you feel a loss of engine power while driving or hear chirping or growling when the clutch is engaged, consider having your car inspected by a service professional.

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