Signs of a bad flywheel include a burning smell, gear slippage and clutch vibrations. These symptoms can present themselves together or separately.
The clutch flywheel is an important part of a vehicle that has a manual transmission. Its job is to store rotational energy that produces power to the transmission. There are some signs and symptoms drivers can look for that will tell them when the flywheel needs to be replaced.
A burning smell is caused when too much heat is produced by the clutch facings. The odor, which smells similar to burnt toast, is caused by "riding" the clutch while driving, which causes the flywheel to wear out prematurely.
Gear slippage is very noticeable while driving. It is caused when the transmission is unable to shift to the next gear, so it often slips into the previous gear. When cased by a bad flywheel, gear slippage causes plate grinding, and the driver or a mechanic may find small metal shavings in the transmission fluid.
Clutch vibrations can be felt in the passenger compartment of the car while driving. They are typically caused by the spring mount mechanism on the flywheel failing, and will greatly reduce the flywheel's performance when the driver depresses the clutch.