It can be troublesome when your ride is anything but smooth and enjoyable. Car jerking is one complaint that is sure to ruin even the shortest drive. It’s even more alarming if the car jerks when slowing down, but it may not be difficult to figure out what’s wrong.
In this guide, we examine the top causes of jerking when slowing down the car. We also look at how to fix the jerking sensation and give you answers to popular questions.
Leaking or Defective Transmission
As the vehicle slows down, jerking could be stemming from issues with the transmission. If you have an automatic transmission, the first possibility is that the fluid is low or dirty. As the car is downshifting, you may notice it’s not as smooth as normal without the right amount or quality of fluid.
Many transmission leaks come from the pan gasket, which naturally wears out over time. If there’s not a leak, there’s also the possibility that there’s something internally wrong with the transmission. It’s possible that the gears and inner parts are worn from old age.
Worn-Out Clutch
The clutch is responsible for engaging and disengaging the engine during gear changes. The clutch is also needed to transfer torque to the engine from the transmission. As the clutch starts to wear out, you may notice more trouble when shifting gears, known as a slipping clutch, and may experience a jerking sensation.
If you have a manual transmission vehicle, you may notice other symptoms of a bad clutch. The pedal can start to feel soft when you step on it. There could also be grinding sounds when the clutch is applied.
Bad Throttle Body
The throttle body helps adjust how much air is entering the engine. The majority of today’s vehicles have a single throttle body, but there are some that contain multiple. As time goes on, carbon builds up in the throttle body. If it becomes too contaminated, it’s not going to be able to regulate airflow normally, leading to a jerking sensation.
You may notice it more when slowing down or accelerating. At the same time, one of the main bad throttle body symptoms includes a drop in fuel economy since the engine doesn’t have the proper air-fuel ratio.
Worn Engine Mount
The motor mount supports and secures the car engine in its place. These mounts are needed to absorb the vibration and shock felt from the engine moving. As a mount goes bad, there are going to be more strange movements that could create a jerking sensation.
You may feel this unusual movement more when slowing down or accelerating as the engine jerks into place. At the same time, you may hear clunking sounds coming from the engine bay.
Failing Ignition Coils
Ignition coils take the power from the car battery and send it to the engine cylinders. Coil packs replaced the old distributor system back in the 1990s. Today, cars can have one or several coil packs, or they are equipped with ignition coils, but none of these are designed to last forever. In most cases, the coil packs may last about five years as they are exposed to constant heat.
When these coils get damaged or start to fail, you’ll notice erratic idling and misfiring. These issues may be felt more prominently as the engine starts to wind down, such as when you are coming to a stop.
Defective Brake Pads or Rotors
If you notice the jerking only when trying to stop, it’s possible that there’s an issue with the brake system. Bad brake pads or rotors can lead to a jerking sensation as you slow the vehicle. When the pads are worn out, you may also hear a squeaking sound as you step on the pedal, while bad rotors tend to make a lower, grumbling noise.
Not only will the brakes get worse and more damage can occur if continuing to drive this way, but the ability to stop will eventually be hindered. That’s why you should always repair brake issues at the first sign of trouble.
Failing Anti-lock Braking System (ABS)
The anti-lock braking system has helped gain better traction and it keeps the wheels from locking up. However, when the ABS fails, it can lead to other issues, even jerking and vibration while slowing down.
If you see the ABS warning light on the dash and notice jerking, you know there’s an issue with this system. Because you want the ABS to work, especially when the roads are slippery, it’s important to have this problem repaired as soon as possible.
Bad Wheel Bearings
The wheel bearings are needed to make sure the tire, hub and wheel assembly all work together to spin the wheel. When a wheel bearing goes bad, it’s normal to feel some vibration and jerking, especially while slowing down.
You may also hear a strange grinding sound coming from that wheel. At the same time, excessive tread wear occurs and the steering can feel loose.
How To Fix Car Jerking
The most important step is to remain calm and don’t panic. Once jerking starts, you want to check the transmission fluid and look for leaks. You should also inspect and repair the brakes if the jerking only happens when stopping. Otherwise, you may want to clean the throttle body or visit a local mechanic.
Don’t Panic
At the first sign of jerking, you want to take action, but you need to do it with a clear head. Panicking is only going to make the situation worse.
If you are on the road, pull over in a safe location and decide the next steps. If you feel it’s safe to drive home, do so cautiously. Otherwise, it may be best to call a tow company, especially if the Check Engine Light is on or there are serious drivability concerns.
Check Transmission Fluid
The next step is to check the transmission fluid. If it’s low, go ahead and add some more. If the fluid looks contaminated, it might be time for a change. You also want to inspect the system for a leak.
Sadly, there are many modern transmissions that are sealed and aren’t simple to check. In this case, you may need the help of a mechanic to check the fluid.
Inspect/Repair Brakes
If the jerking is only happening while you are braking, it’s time to inspect the pads and rotors. If the pads are worn, it’s time to replace them before damage is done to the rotors.
Once the rotors are warped or damaged, you only have two options. You can replace them or resurface the rotors. However, resurfacing only works if there’s enough thickness left on the rotor. When in doubt, it’s best to replace them.
Clean Throttle Body
If the throttle body has a buildup of carbon, you can clean it at home. There are special throttle body cleaners you can purchase and the job is simple.
Cleaning the throttle body should be done every 75,000 to 90,000 miles. If you have an older vehicle that has never had the throttle body cleaned, it might be time.
Replace Ignition Coils
If your car hasn’t had a tune-up in a while, there could be an issue with an ignition coil. You can remove them and test them with a multimeter to see if there’s a fault.
While you can replace one ignition coil that’s causing the problem, it may be best to replace them all. This is a good practice if the coils haven’t been changed in a while and the car has a lot of miles on it. Otherwise, you may run into the same problem as another coil goes bad.
Visit a Mechanic
Some of our suggestions aren’t meant to be diagnosed or fixed by an inexperienced person. If you don’t have more than basic mechanical knowledge, we don’t recommend working on the clutch, ABS or wheel bearings.
If the basic fixes don’t help reduce the jerking, it’s time to reach out to a local mechanic. After a quick diagnosis, they should be able to tell you what’s wrong. At that point, you can decide if the fix can be done at home or if you need to pay them for the repair.
Why does my car jerk when slowing down?
There could be issues with the transmission or braking system. It’s also possible that there’s a clutch malfunction, a contaminated throttle body, bad ignition coils or a faulty wheel bearing. If the ABS light is on the dashboard, this system could be defective, leading to jerking sensations.
Is car jerking a transmission problem?
A jerking car can be related to the transmission. It’s possible that the transmission fluid is low or contaminated. There’s also the chance that there’s internal damage and the gears are slipping, causing trouble engaging. There could be other mechanical problems to blame too, such as bad brakes, a faulty wheel bearing, defective ignition coils, or malfunctioning ABS.
Why does my car jerk back when I stop?
If the jerking only occurs when you are pushing down on the brake pedal, there could be an issue with the pads or rotors. Check the braking system and repair the issue. If the pads and rotors aren’t bad, don’t overlook the fluid level, ABS and wiring, all of which can cause similar symptoms.
Will low transmission fluid cause the car to jerk?
As the transmission fluid gets low, the vehicle can start to jerk and act erratically, especially while downshifting. Check the transmission fluid levels and top off if needed. Even if the fluid level is correct, contamination can cause some of the same symptoms, so you may want to change it.
Jerking sensations can be a scary thing to deal with while driving. If they become too erratic, you may start to worry about controlling the vehicle. That’s why it’s important to take action at the first sign of a rough drive. While many issues can lead to jerking while accelerating, there are also some that occur when slowing the vehicle down.
A quick inspection may reveal the problem and hopefully, it’s something simple to fix, such as low transmission fluid or a dirty throttle body. There’s also the chance that the brakes are to blame or the car needs a new ignition coil. Yet, there are also more advanced issues that you may not be able to tackle on your own. Don’t hesitate to seek out professional help when needed.
Categories: Troubleshooting
