(Updated on July 21, 2021)
If you drive a manual transmission vehicle then you are familiar with the clutch. You will only find a clutch pedal in a manual vehicle because it is required for disengaging and engaging power to the wheels from the engine at certain times while driving.
Normally, you need to apply some pressure to the clutch pedal for this disengagement to take place. But if you don’t even need to apply much pressure to the clutch for it to disengage the engine, or the clutch disengages at higher engine loads without depressing the clutch pedal, your clutch may be slipping.
This condition is often seen in vehicles which frequently drive in congested traffic, cars with newer drivers, high performance vehicles that are driven hard, and cars with upgraded engines making well beyond their factory power level.
If any of these conditions apply to you, then don’t be surprised if you have slippage issues with your clutch.
What Does it Mean When a Clutch Slips?
A clutch is designed to hold a certain level of engine torque, commonly measured in foot pounds (lb-ft) or newton meters (N m). A pressure plate is used to hold the clutch against the flywheel, thereby spinning the transmission input shaft and the engine at the same speed.
Clutches are designed with a friction material on both sides that will grab onto the metal pressure plate and flywheel surfaces. As a clutch wears it loses this friction material, much like your brake pads would.
At some point, the clutch won’t hold the same amount of torque it used to. When the torque of the engine exceeds the maximum torque a clutch can hold, the clutch will begin to slip intermittently under higher engine loads.
Instead of grabbing the flywheel and pressure plate, a worn clutch will allow the engine to spin freely, even when the clutch pedal is fully released. This phenomenon is often most prominent in a mid range gear such as third or fourth, and will get progressively worse over time until the clutch is replaced.
In extreme cases, a worn clutch can leave you stranded, as the vehicle will be unable to get the engine power to the ground.
Top 5 Symptoms of a Clutch Slipping
It is important that you notice a slipping clutch before it causes any serious problems for you or your vehicle. You wouldn’t want the engine to disengage from the drive wheels while you’re traveling at high speeds. That could potentially cause an accident.
So, try to recognize the symptoms of this issue so that you can work on changing your driving habits and getting the problem resolved. Here are five common ways how to tell if the clutch is slipping.
1) RPM Increases But Speed Doesn’t
One easy way to test whether you have a slipping clutch is to take note of your engine’s RPM. If you step on the gas pedal to accelerate and your RPM go up quicker than normal while your driving speed doesn’t increase like it should, you probably have a slipping clutch.
For instance, you could cruising along on the highway and decide you need to pass a slower vehicle. When you try to accelerate, your RPM jumps higher and your engine makes more noise but your car doesn’t go faster. A slipping clutch is usually more obvious in higher gears when you attempt to accelerate.
2) Burning Smell
When the clutch slips, there will be a burning smell coming from the front of the car. This is due to all the excess heat generated from the constant disengagement of the engine and the slipping of the clutch.
The more the clutch slips, the worse the burning smell is going to get. You don’t want to drive with this smell in the cabin because it will make you nauseous. The more the clutch slips, the worse the condition will get.
3) Poor Engine Performance
The ultimate test is when you’re pulling a heavy load in or behind your vehicle. Normally, this would require the engine to send a lot of power to the drive wheels.
But if your clutch is slipping, the engine will not be able to deliver this power. Then you will have almost no acceleration because of this lack of engine power. You can reduce the load that you’re pulling to increase the power somewhat, but it will not be a permanent fix.
4) Clutch Pedal Height Difference
As you drive your vehicle, you should be used to the height of the clutch pedal from the floor. When you press down on the pedal and take your foot off, the pedal should always return to the same height that it was before.
If you ever notice the height start to change, whether the pedal is too high or too low, then something is definitely wrong with the clutch. In most cases, it will be due to clutch slippage.
You can try adjusting the clutch pedal to see if it helps, as this is much cheaper and easier than dropping the transmission for a clutch replacement.
5) Quick Disengagement
The biggest symptom of a slipping clutch is quick disengagement between the engine and drive wheels. When the clutch is normal, you would need to press down the pedal about 1 to 2 inches before the engine is disengaged.
However, with a slipping clutch, the engine will disengage after you lightly press the clutch pedal down less than one inch. Sometimes just resting your foot on top of the pedal will be enough for the engine to disengage.
How Do I Fix a Slipping Clutch?
There is pretty much only one solution to fixing a slipping clutch, and that is clutch replacement. Sometimes a leaking rear main seal will cause a good clutch to slip (as the clutch may be lubricated in engine oil), but usually you will just replace the clutch while you’re in there; the mechanic has to drop the transmission to replace the rear main seal anyway, and the cost of parts for a clutch job isn’t very high.
You will also want to consider resurfacing or replacing the flywheel and pressure plate, as these parts can degrade from use. If the clutch is worn down to the rivets, chances are the excessive heat and metal-to-metal contact will damage the flywheel and warrant replacement.