Of all the possible symptoms to experience in a vehicle with a manual transmission, clutch chatter may be one of the most frustrating. While many other clutch-related signs point to worn-out friction material on the clutch surface or a damaged flywheel, clutch chatter isn't quite as simple to pin down. Since clutch chatter is less common than slippage, many drivers may not even be aware of what they are experiencing. If you think that your manual transmission vehicle may be suffering from chatter, keep reading to learn more about this condition and its possible causes.

What Clutch Chatter Is

You may not have heard the term before, but clutch chatter is unmistakable once you have experienced it. Chatter usually occurs as your vehicle is engaging first gear, right as you reach the friction point. In some cases, chatter may occur shortly after hitting the friction point, as your clutch "hooks up" entirely. Light chatter may feel like a slight vibration that prevents you from getting your car moving smoothly, while severe chatter may be extraordinarily violent and felt throughout the entire vehicle.

It is sometimes possible to compensate for chatter by revving the engine higher while engaging the clutch, but this can cause rapid wear or damage to the clutch surface or other components. In some cases, very slowly letting off the clutch may cause it to chatter more severely, and it may be impossible to get going smoothly with very little gas.

The Causes of Chatter

There are two primary reasons that you may be experiencing clutch chatter, although there are a variety of underlying conditions that can cause them. The first, and most common, is "skipping." Skipping is similar to a slipping clutch, except that your clutch is momentarily making contact and slipping again before locking. This situation is commonly caused by contamination of the clutch, such as if oil or another fluid finds its way onto the clutch disc surface. A glazed clutch with smooth spots may skip in this way, as well, and clutch chatter is sometimes an early symptom of a clutch that is wearing out.

In addition to a skipping clutch, chatter may also be the result of failures elsewhere in the drivetrain. A failing driveshaft or joint or an issue with your differential may also cause apparent chatter. In this case, chatter occurs not due to a problem with the clutch, but due to vibrations as other components in your drivetrain take up the rotational energy transmitted by your transmission.

Diagnosing Chatter

Diagnosing the underlying cause of chatter is not always straightforward. A skilled transmission technician will most likely perform a road test to determine if the chatter "feels" like the source is the clutch or elsewhere in your drivetrain. Since clutch replacements are not cheap, technicians will also thoroughly inspect the underbody of your vehicle for leaks and worn components before removing and disassembling your transmission.

To learn more, visit a local transmission shop like B G & S Transmissions.