Not only can a bad clutch leave you stranded, it can also cost hundreds of dollars to replace. That is why it is imperative to know how to tell if your clutch is going bad and take immediate action before it wears out. If your clutch shows any signs of failure, the sooner you act, the better off you will be.
Check the feel of your clutch pedal. A major warning sign of a bad clutch is if your pedal feels "squishy" or if your clutch doesn't engage until you've let the pedal almost all of the way out. Drive your car around the block, checking for these warning signs.
Watch for a burning smell. If your clutch is going bad, you may smell something akin to burning newspaper. This smell indicates friction from a slipping clutch.
Check for problems when you shift. As you shift your car, a bad clutch will not engage smoothly and will shake a little bit.
Remove the inspection cover to check fro abnormal wear. In some cars, there is a plastic cover located on the bottom of the bell housing. (The bell housing is the part that holds the clutch and is bolted to the engine block.) This plastic cover is called an inspection cover and can be popped off to view the clutch. Remove the inspection cover with a flathead screwdriver and look for any signs of abnormal wear. If your clutch is going bad, there will be substantial visible damage---not just black powder.
Remove the transmission. Beyond these indicators, the only other way to check if your clutch is going bad is to remove the transmission. Unless you have advanced automotive knowledge and equipment, this will need to be done at a transmission shop.
Many local transmission shops offer free clutch diagnostics. A professional mechanic will check the clutch cylinder to see if the clutch needs to be adjusted or completely replaced.
A bad pressure plate, slave cylinder, clutch cylinder or throw-out bearing can often be mistaken for a bad clutch. This is why a professional mechanic may be your best option to determine a course of action.