Any owner of a manual transmission will tell you they’re a blast to drive, but they do have a weakness — the clutch that makes manual control possible will wear out over time. Worse yet, many systems are designed so that a simple glance under the vehicle won’t reveal the problem immediately when clutch failure is already underway.
Clutch replacement on a stick shift is an inevitability, especially on older cars, and not a quick fix. Luckily, clutch failure is usually a slow process, showing signs over a long period rather than one day leaving you stranded without warning; however, clutch problems left unchecked will result in just that.
So you just need to know what to look for.
The clutch is what mates engine speed to the selected transmission gear. When the pedal is depressed, the clutch disengages, allowing for a change of gears. Importantly, the clutch is only one part of a closely related drivetrain system. Surfaced in friction material similar to brake pads, the clutch definitely takes more abuse than related components, but because the system is so integrated — and such a pain to get to — many mechanics recommend changing other parts that often come bundled in a kit during clutch replacement to save time and money in the future.
Signs of Failure
There are a number of things that can go wrong with a clutch and, because so much of the wear depends on driving style and conditions, it’s difficult to know exactly when a clutch will fail. One classic sign of failure is a burning smell, much like cooked brakes. When the friction material has worn down to the rivets holding it in place, it will slip and spin in contact with the flywheel instead of engaging it, generating a great deal of heat from the friction.
Another early giveaway is a spongy clutch pedal. Since the friction material has worn, the pedal must travel farther than usual to disengage. This also creates a difficulty shifting — the car might have sporadic problems shifting (especially in first and reverse) or fail to shift smoothly.
If you remove the inspection plate under the bell housing, you can see part of the clutch that might help you determine wear. It’s normal to find black dust in that area, but if the friction material has worn to the level of the metal rivets or is clearly wearing unevenly, it’s time for a change. In the event of uneven wear, you likely have another problem in the system that needs to be addressed in addition to clutch replacement. Same goes for leaks. If the system is leaking, simply replacing the clutch will do you no good.
Test it Out
To weed out a worn clutch among other possible failures, such as worn bearings, stuck linkage, bent release forks and a number of other maladies, try the following: take the vehicle to a secluded road and drive it in first gear. Then, rev the engine and quickly move into fourth or fifth gear. If the vehicle stalls or shakes because it’s too high a gear without the speed, your clutch is fine. If, however, the engine revs smoothly without going into gear, this means the clutch is not properly engaging and is likely worn, warranting clutch replacement.
Check out all the drivetrain parts
Photo courtesy of Flickr
Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter. In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.