Has your manual transmission car started feeling a little odd when shifting gears? Do you notice the engine revving higher than normal before the car starts moving? A slipping clutch could be to blame and it will only get worse over time.
Knowing how to identify the distinct symptoms of a clutch that’s slipping early on can help you get ahead of bigger problems and avoid a breakdown on the road.
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.
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.
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.
What Causes a Slipping Clutch?
There are a variety of things that can cause your clutch to exhibit signs of slipping which include driving styles and shifting habits. Here are the most common causes:
Worn Clutch Disc
Over time, the friction material on the clutch disc can become worn down. This reduces the ability of the disc to grip the flywheel and pressure plate, allowing it to slip when torque is applied through the transmission.
Riding the Clutch
Resting your foot on the clutch pedal while driving puts constant pressure on the clutch. This can cause it to overheat and slip. It’s better to fully depress the clutch when shifting and then fully release.
Weak Clutch Springs
The clutch disc is squeezed between the pressure plate and flywheel by springs. If these springs become weak or broken, they won’t apply enough force to prevent slipping.
Launching From a Stop
Quickly releasing the clutch and trying to aggressively accelerate from a stop places a lot of stress on the clutch components. This can lead to premature wear and slipping. Sure, burnouts can be fun but there are consequences.
Low Clutch Fluid
Clutches use hydraulic fluid to engage and disengage. If the fluid level is low, the pressure plate may not fully engage the clutch disc.
Oil Contamination
Oil or grease on the clutch disc can prevent it from gripping properly. A leak from the rear main seal could cause oil to contaminate the clutch.
Overheating
Excessive heat buildup, from heavy loads or riding the clutch, can glaze the clutch disc material reducing grip. This is commonly referred to as clutch fade.
Poor Shifting Habits
Not fully depressing the clutch when shifting, shifting to the wrong gear, or releasing the clutch too quickly can cause the clutch to slip as it tries to match engine and transmission speeds.
Downshifting Incorrectly
When downshifting, the engine speed needs to be increased to match the lower gear ratio before releasing the clutch. If the clutch is released before the engine speed increases, the clutch will slip.
Towing or Hauling Heavy Loads
Using the clutch to start from a stop with a heavy load in the vehicle can lead to overheating and slippage over time. The load puts additional strain on the clutch.
Preventing Future Clutch Slippage
To avoid clutch slippage down the road, start by regularly checking your clutch fluid. Low levels can cause slipping, so keep it topped off with the factory-specified fluid.
Also, focus on smooth driving. Avoid aggressive launches or careless shifting that can prematurely wear the clutch. Instead, be gentle with the pedal and make deliberate gear changes.
Stay on top of maintenance as well. Have a mechanic inspect the clutch system during routine visits. Early detection of any issues can prevent slipping.
When the time comes, invest in a quality replacement clutch rather than going with the cheapest option. A robust aftermarket kit will provide better grip and longevity.
FAQs
Can the Clutch Slip In an Automatic Transmission?
Though automatic transmissions lack a manual clutch, they can still experience slippage issues similar to those in manual vehicles. Instead of a clutch, automatics use a torque converter and transmission fluid pressure to change gears, so problems like low fluid levels or a malfunctioning torque converter can cause gear slippage.
Just like inspecting the clutch on a manual, it’s important to check transmission fluid regularly and address any slipping issues promptly in an automatic. With proper maintenance and care, slippage can be prevented in both transmission types.
Slipping vs Riding the Clutch: What the Difference?
When you experience a slipping clutch, it means the clutch isn’t properly transferring power from the engine to the transmission. This results in the engine revving more than it should, while the car doesn’t go faster. You’ll usually notice a rise in RPMs without a corresponding increase in speed, a foul burning smell, or a disconnected feeling between the gas pedal and acceleration.
On the other hand, riding the clutch is a poor driving habit where you constantly keep your foot on the clutch pedal, even when it’s not necessary. This could lead to faster wear on the clutch, which may contribute to clutch slippage in the long run. Avoid riding the clutch by releasing the pedal in between gear changes or when not actively using it to maintain the clutch’s integrity.
Why is My Brand New Clutch Slipping at High RPM?
There are couple reasons why your new clutch is slipping at high RPM. First, it might be that the clutch hasn’t been adequately broken in yet. It’s important to give your new clutch time to wear in properly, which might require between 500 to 1,000 miles of easy driving. Avoid aggressive acceleration and high RPM during this period.
Faulty installation may be another reason. In some cases, improper alignment or incorrect torque settings may lead to excessive wear or poor clutch performance.
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My clutch at chev utility 2012
Start to show some different height and I would like to ask what might be the problem on a car as the car had no power while changing gear.
That’s normal. There will be some height difference as eventually more and more metal scrape of the clutch parts and gears/layshaft. It does mean your clutch might need replacement rather sooner than later