From weird noises and unresponsive controls to faulty components – a lot can go under the hood of your car. One of the more common issues is shaking or vibrating while your car is in reverse, but what causes it?
Sudden or constant shaking, while your car is in reverse, may be caused by damaged suspension, clutch or transmission. It can also be caused by a more physical problem that’s easier to identify, such as low transmission levels, old spark plugs or worn tyres.
If you want to learn more about what causes the problem and how to diagnose it, continue reading below.
Is it Normal for a Car to Shake While in Reverse Gear?
No, cars shaking while in reverse is not normal and is often symptomatic of an underlying problem within the car; generally a problem with the suspension or drivetrain.
Other factors may also cause this, such as uneven tyre wear and worn-out brake pads. It is normal to be concerned when this happens, as it is a safety concern. Thankfully, there are ways of identifying what is causing the vibrations.
What are the Most Common Reasons a Car Shakes When in Reverse?
Due to the nature of a car, there are many reasons why a car would shake during reverse. As such, checking for causes usually calls for a full vehicle maintenance service.
1. Loose or Damaged Suspension
Damaged suspension components are one of the most common causes of shaking during reverse. Damage to suspension parts such as the bushings, shock absorbers, and struts will prevent the proper absorption of vibrations, resulting in a shaky ride, not just while you are reversing.
Unusual and consistent vibrations are generally caused by problems with the suspension system and aren’t something that can be repaired or replaced without the help of a professional. If you suspect a problem with your car’s suspension, have it checked by your mechanic.
2. Damaged or Worn Clutch
Another common cause of shaking in reverse is a worn-out or faulty clutch. This is the mechanism that connects the engine and the transmission together. It is composed of two plates on each side of the flywheel and is compressed when the brake pedal is pushed.
The friction between the surfaces allows the transfer of power from the engine into the transmission and then into the axle. When the clutch is worn down or becomes faulty, it causes excessive vibrations when accelerating and decelerating in reverse gear, as one of the plates is likely not able to engage fully.
To fix this problem, you can either purchase a new clutch at a store and replace the old one with guidance from your owner’s manual or replace the clutch master cylinder with a new one. If your car still vibrates too much after either or both are replaced, then it is a sign that another problem is causing it.
3. Worn Transmission
Whenever you put your car into reverse gear, the torque given by the engine is much higher than any other gear mode, which could (and in most cases, would) actually wear out the car’s transmission mounts.
Worn or damaged transmission mounts will cause engine vibrations to be transferred directly into the chassis since the mounts cannot absorb them anymore. This is an issue that will persist unless the mounts are replaced.
You can check if the mounts are damaged by following these steps:
- Push your left foot hard on the brake while the gear is shifted to drive mode. Then, accelerate the gas pedal with your other foot – the engine RPM should reach or exceed 2,000.
- Put the car in reverse and repeat the step above. Doing these two steps in succession will make identifying and isolating vibrations in different areas within the engine bay easier.
- Slight rocking of the engine is expected, but if you experience excessive shaking during the 2nd step, then it is a sign of a bad mount and would need to be replaced.
4. Damaged Spark Plugs
Not many people know that spark plugs can cause shaking as well. Spark plugs in bad condition (e.g. dirty and with a bad build-up of carbon deposit and dirt) will prevent fuel from being ignited as the plugs will not be able to fire properly. The engine misfiring that happens during this time is what gives the shaky feeling even at idle.
If you have not replaced your car’s spark plugs in a while, it will be most beneficial to do so. There are different types of them on the market, so make sure you purchase the right one for your car. Remember to consult the owner’s manual for the specific type of spark plug.
5. Low Transmission Fluid Levels
If your car has automatic transmission, the transmission fluid plays a critical role in engaging and disengaging the transmission from the engine. If you have not checked your fluid levels or replaced the transmission fluid in a while, then it’s time to check them. If the fluid levels are below what is suggested by the manufacturer or below a designated level in the owner’s manual, then it is highly likely that the fluid levels are playing a part in the shakiness.
There are some cases in which a leaking seal inside the transmission reduces the pressure build-up when engaging in reverse, which would also cause the transmission to shake during reverse. Inspect the transmission fluid pressure at idle, stall, and reverse to understand what is going on inside. If you’re not sure about your fluid levels or pressure, then it’s best to have your car checked by a professional.
6. Unbalanced Wheels
As the only part of your car that actually makes direct contact with the surface of the ground, they are as likely a culprit in excessive vibrations as parts such as the transmission and suspension. Tyre bulge, or the tyre rubbing against the inner fender, may cause some shaking during reverse.
In some cases, uneven or insufficient air pressure within the tyres will also cause a vibration when rolling over surfaces. Lastly, damaged, deformed, or worn-out tyres can be visually inspected by looking at the tread depth. Another test you can do is to insert a coin into the tread grooves; if it goes in without much resistance, it needs to be replaced.
7. Malfunctioning ECM
An Electronic Control Module (ECM) is responsible for many engine functions, such as fuel injection and ignition timing. A malfunction in the ECM is often caused by faulty throttle body sensors.
These sensors are mounted onto the throttle body and are important in ensuring the ratio of the air-fuel mixture, which in turn ensures proper combustion of the fuel within the piston-cylinder arrangements.
The sensors that facilitate ECM operation to control the ratio of air and fuel properly are the:
- Manifold Absolute Pressure (MAP) Sensor
- Mass Air Flow (MAF) Sensor
- Throttle Position (TPS) Sensor
- Idle Air Control Valve
The malfunction of any of these sensors will affect the ECM and, consequently, the engine’s functioning, causing an improper air-fuel mixture that leads to a shaking feeling during reverse.
8. Damaged Drive Shaft
Since the drive shaft is responsible for transferring power from the transmission into the rear differential, a faulty axle or drive shaft will often cause shaking when in reverse. To check for problems, look for cracks, bends, excessive play, or signs of corrosion. If you see any of these on your driveshaft or axle, it is time to have them replaced.
What Can I Do If My Car Shakes While in Reverse?
The main things you can do as a car owner if your vehicle shakes while in reverse are:
- Avoid Revving the Engine – When the car’s engine is revved, the engine is actually physically moving around. This means there will be more vibrations, especially if your engine mounts are worn out and need to be replaced.
- Reduce How Much You Drive – While this may sound like a no-brainer, reducing how much you drive is one of the best and safest things you can do if your car shakes while in reverse.
- Visit a Mechanic As Soon as Possible – Since worn components can be a disaster to deal with if something happens while you’re on the road, visiting a mechanic should be done as soon as the problem presents itself. Neglecting this may cause problems for you and other people on the road.
- Avoid Accelerating Suddenly – Sudden acceleration produces torque in such a short amount of time and without build-up that the engine will vibrate heavily. Again, if your drivetrain components are worn out or malfunctioning, no vibration will be absorbed, and you will feel all of it inside the car.
- Review Your Regularly Scheduled Maintenance Plan With Your Mechanic – As with everything; prevention is the best cure. Being on top of your car’s regular scheduled maintenance and check-up is the best way to know if a component is about to fail, transmission fluids are running low, or tyres are running thin, among others.
Is it Dangerous to Drive a Car that Shakes in Reverse?
Yes, if the vibrations are excessive, it is dangerous to drive because the vibrations are always caused by something damaged, insufficient, or malfunctioning with one or a couple of the car’s components. It could be a problem with the engine, transmission, driveshaft, transmission fluid, and tyres, among others.
Should I Take My Car to a Mechanic If It’s Shaking While in Reverse?
Generally speaking, there are underlying safety issues in a car that abnormally and constantly vibrates when in reverse. The failure of one or more components in a car that causes vibrations can cause accidents at any point in time, which is why an immediate mechanic visit is imperative.
Related Questions
Why Does My Car Vibrate in Reverse When It’s Cold?
In cold weather, engine temperature will cool to the surrounding temperature because of a decline in the coolant and engine oil temperature, which starts a series of processes that causes the engine to idle high until the car’s engine warms down during engine start.
What Causes a Car to Shudder While Driving?
The most common cause is damaged tyres due to air pressure and varying stages of wearing out. However, it could also be caused by problems on the wheels, the suspension, the driveshaft and axle, and the engine.
