Whenever your car jerks, this is not a pleasant experience. The problem with the jerking vehicle shouldn’t be ignored because it can lead to monstrous consequences. In this article, I will tell you about the reasons and possible aftereffects of your car jerking when it’s slowing down.
In short, a car may jerk when slowing down because of problems with the transmission, clutch, damaged engine or transmission mounts, or faulty engine sensors. It means that to diagnose the problem, you will need some professional help or experience as a car mechanic.
In this article, I will cover the following:
- Symptoms of the car jerking when slowing down.
- What are the common reasons for the problem?
- What if I ignore the jerking car and keep driving?
- Best ways to fix the issue and avoid transmission damage.
Registering the symptoms of your car jerking when slowing down
First of all, we need to understand that we are on the same page. I will be talking about the situation when you release the gas pedal and your car starts slowing down. But then, at a certain or random moment, the vehicle starts jerking. This may be just a slight movement that you barely feel in the car or a problem that requires immediate action and affects your comfort.
Usually, the jerking is rhythmic and it happens only for a certain amount of time. After the car slows down more, the jerking stops getting on your nerves and you can drive further.
Of course, this is not a pleasant situation because you understand that this shouldn’t happen with your vehicle. This is especially alarming when you notice this suddenly after happily driving your car for several years without experiencing such an issue.
What are the possible reasons for your car jerking when slowing down?
I’ve looked at what other bloggers write about this problem and was disappointed to see that they blame fuel supply or ignition. This is impossible because when you release the gas pedal and the car is moving, the fuel supply is cut and the ignition stops working for some time. This is made for fuel economy.
Your wheels give the engine the needed energy to run and it runs with the power of inertia. Well, you can check this by looking at the immediate fuel consumption screen on your trip computer. It will show zero gallons or liters per hour for some time. So, it just can’t be the ignition or the fuel supply.
Let’s see what can be the culprit:
1. Transmission
Unfortunately, the most obvious problem that causes your car to jerk when you slow down the vehicle is the issue with the gearbox. You may have manual, automatic, DCT, CVT, or any other kind of transmission in your car. But the jerking problem can still be there.
In a manual transmission, the issue may be with the wrong shifting. For example, if you go 50 MPH and suddenly shift to the second gear, the RPM will skyrocket immediately and the car will start jerking.
There is a whole bunch of possible problems with the automatic transmission:
- the torque converter is faulty and needs repair or replacement;
- low transmission fluid level causes problems;
- the gearbox is overheated and needs cooling down before you drive further;
- transmission sensors are faulty and command the transmission to engage the wrong gears;
- the band or chain is faulty (stretched) in the CVT unit.
I can continue listing these problems but it will just take your time. Any of these problems offers a good DIY solution. You will still need to go to the dealership or repair shop and find a person who knows how to diagnose the transmission and solve your problem.
Almost any part of automatic or manual transmission may lead to jerking when slowing down. This is one of the most important symptoms that you should notice and pay attention to.
2. Clutch
While there is no clutch in the CVT or the torque-converter transmission, clutches are used in DCT and manual gearboxes. If the clutch is done, it will show you quite a lot of other symptoms. But one of the first symptoms that may appear is jerking when slowing down.
All energy that is transferred through the transmission to the wheels and also from the wheels to the engine comes through the clutch. If something is wrong with the pressure plate or other parts of the kit, you may feel some jerking when the car is slowing down. It starts with barely noticeable jerking and develops into serious problems that are hard to ignore.
3. Flywheel
In some rare cases, a faulty flywheel may also cause such issues as jerking when decelerating. This usually happens with DCT gearboxes but may also show up in other transmissions. Flywheels just need to be replaced when they are going crazy but the problem is that you will not be able to locate this problem by yourself.
Also, replacing the flywheel in your car is not that easy and you will most likely need some professional help with this.
4. Engine and transmission mounts
This is quite a primitive cause but it’s really possible. There are several mounts under the hood of your car that are holding the engine, the transmission, and other units that are placed there. It may well be that one of those mounts is bad and now the engine shakes when you change the speed. When the car sharply decelerates, the engine moves forward and starts shaking. This may cause the effect of jerking.
Also, the shaking engine may not work efficiently. When it shakes, the ignition and fuel injection may start malfunctioning and creating problems.
5. Car ECU issues or engine sensor problems
When you release the gas pedal and the car still moves, the ECU has to cut off the fuel supply or reduce it significantly because the engine gets the energy from the wheels and can rotate without the help of burning fuel. If the ECU or one of the sensors is faulty, this may lead to situations when the fuel supply is not cut off and the fuel keeps burning.
This will create problems because the engine will have too much energy and will not be able to get rid of it by sending it to the wheels. That’s why it can jerk for some time.
This problem should be diagnosed with the help of the OBD2 scanner. Usually, you can easily locate these problems and know which exact sensor is going crazy. If it’s all about the ECU, it will be harder to locate and repair.
Can I keep driving when the car jerks when slowing down?
Well, I don’t recommend ignoring this because even slight jerking can be the symptom that tells you about a serious upcoming problem. But while it’s not showing up now, you can still prevent this problem.
Investing in repairing a slight problem is much better than spending lots of money on changing an expensive unit or module in your car.
Once you notice jerking in your vehicle, notice if it’s intensive or just unnoticeable. If the jerking is bad and makes it uncomfortable to drive the car, just stop and don’t drive further. If it’s just mild, you can drive to the trusted repair shop or to the dealership and solve the problem without paying for the tow truck.
How can you fix jerking in your vehicle?
Once you notice that your car started jerking when slowing down, you should do the following:
- Decide if the jerking is intensive and whether you should stop to save the vehicle from possible damage.
- Arrange a visit to the dealership or to the trusted repair shop. This will help you repair the car as soon as possible.
- Register all the symptoms so that you could tell the mechanic. It will make the diagnosing process easier and cheaper for you.
- Have the vehicle diagnosed. Remember the most common issues that can cause a car to jerk when slowing down.
- Decide if you should repair the diagnosed problem on your own or if you better have the car repaired in the shop.
Unfortunately, there are not many things you can repair on your own. In most cases, you will need some professional help.
Final thoughts
While in most cases the car jerking when slowing down is the result of a problem with your transmission, sometimes the reason for this problem is much deeper and harder to locate.
Whatever the reason, you should go to a professional repair shop or to the dealership. Good diagnosis and proper inspection will help you locate the actual problem and then use professional help to solve it.
If you notice that your car jerks when decelerating, register all other symptoms, and look at possible warning lights or error messages. Anything will be important when trying to locate the reason for such a behavior of your vehicle.