Can Jerks When Shifting To Reverse: Unexpected Jolts!

Are you tired of dealing with jerky movements when shifting your car into reverse? It can be frustrating and even embarrassing, especially when you’re trying to navigate tight parking spots or smoothly back out of a driveway.

Just as you put your car into reverse, it suddenly jolts forward or backward with a jerking motion. 

In this article, we will delve into the various causes of jerking when shifting into reverse and discuss practical solutions to tackle this issue. 

A car jerking when shifting into reverse gear can be caused by low transmission fluid, cold engine start, faulty solenoids/valves, weak battery, worn clutch bands, internal leaks, bad torque converter, damaged mounts, faulty CV joints, clogged filters, sticky valves, or trying to shift before fully stopped. Proper inspection and repairs by a mechanic can identify and resolve the underlying issue.

Also Read: Car won’t move in any gear automatic transmission

Causes Of Car Jerking When Shifting To Reverse

Here are the causes of car jerking when shifting to reverse:

1. Low Transmission Fluid

Transmission fluid is a type of hydraulic fluid that lubricates, cools, and cleans the components of your car’s transmission. It also acts as a medium for transmitting power from the engine to the wheels.

Without enough transmission fluid, your transmission will not function properly and may suffer from overheating, wear, and damage.

Transmission fluid exerts hydraulic pressure on clutches and bands after passing through control solenoids to engage clutches and shift gears.

When you shift your car into reverse, the transmission system engages a different set of gears than when it’s in drive or any other gear. These gears need to mesh together seamlessly for the transition to be smooth.

However, if there is not enough transmission fluid in the system, the clutch pack may not receive enough pressure to engage properly. This causes a sudden jolt or jerk as the clutch pack tries to engage and disengage rapidly.

What other problems low transmission fluid can cause?

Low transmission fluid can also cause other problems in your transmission, such as:

  • Delayed engagement: Apart from the jerking motion when shifting into reverse, there are other signs that may indicate low transmission fluid. These include slipping gears, delayed engagement when shifting, and strange noises coming from the transmission system.
  • Overheating: Transmission fluid helps to dissipate heat from the friction and movement of the parts. If there is not enough fluid, the parts will overheat and cause damage.
  • Wear: Transmission fluid lubricates and protects the metal surfaces from wear and tear. If there is not enough fluid, the parts will rub against each other and cause premature wear.
  • Sludge: Transmission fluid cleans and removes dirt and debris from the system. If there is not enough fluid, sludge will build up and clog the passages and valves.
  • Leaks: Low transmission fluid can indicate that there is a leak somewhere in the system. Leaks can occur due to cracks, holes, loose connections, or worn seals and gaskets. To learn more, you can read my guide on fixing transmission leaks.

How to check the level of transmission fluid?

The approach to verify the transmission fluid level varies based on the vehicle, as certain vehicles are equipped with transmission dipsticks while others lack them.

If your vehicle is equipped with a transmission dipstick, follow these steps to check the transmission fluid level: 

Before checking the transmission fluid, ensure that your vehicle is parked on a level surface. This will give you an accurate reading of the fluid level.

  • Park your vehicle on a level surface and start the engine. Let it run for a few minutes until it reaches the normal operating temperature.
  • With your foot on the brake, shift the transmission through each gear (P, R, N, D, etc.) and then back to Park. This helps circulate the fluid and ensures an accurate reading.
  • Locate the transmission dipstick under the hood. It is usually near the back of the engine and has a red or yellow handle. You can also refer to your owner’s manual for the exact location. Do not confuse it with the oil dipstick, which is usually near the front of the engine.
  • Pull out the dipstick and wipe it with a clean cloth or paper towel. Insert it back into the tube and push it all the way down.
  • Pull out the dipstick again and look at the fluid level and condition. The fluid level should be between the two marks on the dipstick, which indicate the minimum and maximum levels. The fluid condition should be clear and red or pink in color. If the fluid is low, dark, brown, black, or smells burnt, you may need to add or change the fluid.
  • If you need to add fluid, use a funnel to pour the correct type of fluid into the tube where the dipstick goes. Do not overfill the transmission, as this can cause damage.
  • Check the level again with the dipstick and adjust as needed.

For vehicles without transmission dipsticks, follow these steps:

  • Look for the fill plug, which is typically located on the side or bottom of the transmission. Consult your owner’s manual for the exact location.
  • Once you’ve located the fill plug, use a wrench or socket to remove it. Again, be cautious as the transmission may be hot.
  • Insert your finger into the fill hole and check the fluid level.
  • The fluid should be level with the bottom of the fill hole.

How to add transmission fluid if its level is low?

Every vehicle has a different way of adding transmission fluid. So, you have to consult the owner’s manual in that case.

2. Dirty Transmission Fluid

Over time, the transmission fluid can become contaminated with dirt, debris, and other impurities. This can happen due to normal wear and tear, as well as the accumulation of particles from the friction materials inside the transmission.

When the transmission fluid becomes dirty, it loses its ability to lubricate and protect the moving parts effectively. 

Inside the transmission, there is a component called the valve body. The valve body is responsible for controlling the flow of transmission fluid to different parts of the transmission, allowing for smooth gear shifts.

When the transmission fluid is dirty, it can contaminate the valve body, causing it to malfunction. The valve body consists of various valves, solenoids, and passages, which work together to regulate the transmission fluid’s flow.

If the valve body becomes contaminated with dirty transmission fluid, it can lead to improper operation and cause the car to jerk when shifting into reverse.

How to check?

The fresh transmission fluid has a dark red tint. If the transmission fluid is dark brown or black, it means you need to change the transmission fluid.

When you drop the transmission pan, also check if metal flakes are attracted to the magnet inside the transmission pan. In that case, you should clean it with this brake cleaner.

metal shavings get attracted to magnet in transmission pan

Moreover, you should always perform a transmission flush if the transmission fluid color is black.

Lastly, some people forget to drain the torque converter as well. So, you should drain both the transmission pan and the torque converter. A torque converter has a drain bolt from which you can drain transmission fluid.

In the owner’s manual, you will see transmission fluid capacities with and without torque converter. If you drain the torque converter as well, you need to follow the transmission fluid capacity mentioned in the manual.

3. Malfunctioning Torque Converter Lock-up Solenoid

A torque converter lock-up solenoid, also called TCC solenoid, is a valve that controls the fluid pressure inside the converter.

When the car reaches a certain speed, the solenoid activates and engages a lock-up clutch inside the torque converter, creating a direct connection between the engine and the transmission. This reduces the slippage and improves the fuel economy and performance of the car.

However, sometimes the solenoid can malfunction and cause problems with the shifting of gears. One of these problems is car jerking when shifting to reverse. This happens when the solenoid fails to unlock the converter when the car slows down or stops.

As a result, when the driver shifts to reverse, there is a sudden change in torque and direction, causing a jerk or a shudder in the car.

To learn how the lock-up clutch of the torque converter works, you can watch the following video:

How to test TCC solenoid?

You will find a TCC solenoid on the front side of the transmission near the valve body of the transmission.

A TCC  solenoid becomes bad when it is stuck closed or stuck open. This disturbs the flow of transmission fluid through the lock-up clutch due to which it does not disengage when a car comes to a stop.

Here are the steps to perform a TCC solenoid test:

  1. Utilize a digital multimeter to gauge the resistance of the solenoid valve within the torque converter.
  2. Attach the leads of the multimeter to the terminals of the valve.
  3. A resistance measurement falling within the range of 15 to 25 ohms indicates the effective operation of the valve.

An additional way to determine the TCC solenoid valve’s functionality involves the following procedure:

  1. Apply power from a vehicle battery or a comparable power source to the terminals of the solenoid valve.
  2. An audible clicking sound should become perceptible, accompanied by observable movement of the valve’s plunger in a reciprocating manner.
  3. This examination provides confirmation of the appropriate operational status of the valve.

3. Weak Battery

When you shift your car into reverse, several components come into play to ensure a seamless transition. These components include solenoids and sensors that rely on the power supplied by the battery.

Solenoids act as switches that control the flow of transmission fluid, while sensors provide important feedback to the car’s computer system. Both solenoids and sensors require a constant supply of voltage to function effectively.

When your car battery is weak, it fails to provide sufficient power to the solenoids and sensors. As a result, these components may not function optimally or may not receive the necessary voltage at all. This leads to a disruption in the smooth shifting process, causing your car to jerk when shifting into reverse.

When the battery is weak, the control solenoids may not fully engage or disengage the gears as intended. This can cause a delay in gear engagement or even an incomplete engagement. As a result, when you shift into reverse, the gears may clash or grind, leading to the jerking motion you experience. 

How to check?

You should check the voltage across the terminals of your car’s battery with the engine on and off.

Hook up the voltmeter and measure the battery voltage when the engine is off. The voltage on a charged battery should read around 12.5 volts. Now, start the engine and measure the voltage. It should be between 13.5 and 14.5 volts.

4. Malfunctioning Shift Solenoid

shift solenoids of automatic transmission

The valve body in an automatic transmission serves as the control center for hydraulic pressure regulation and fluid flow, enabling smooth gear shifting. It consists of a complex network of passages, valves, and solenoids that work in harmony to facilitate the seamless transition between gears.

The shift control solenoid is one of the critical components within the valve body, responsible for controlling the flow of transmission fluid and engaging specific gears. 

The shift control solenoid acts as an electromechanical switch that receives signals from the vehicle’s computer, also known as the engine control unit (ECU). Based on these signals, the solenoid regulates the transmission fluid pressure, enabling the gears to engage or disengage smoothly.

Here’s how control solenoid in a valve body looks like:

schematic of solenoids in valve body of automatic transmission
  1. Transmission fluid pressure switch
  2. 1-2 shift control solenoid
  3. 2-3 shift control solenoid
  4. Pressure control solenoid 

When you shift your car into reverse, the TCM or ECU sends a signal to the shift control solenoid to open or close a valve that allows fluid to flow into the reverse clutch pack.

This engages the reverse gear and allows the car to move backward. However, if the shift control solenoid is faulty, it may not respond properly to the signal or it may leak fluid.

When the shift control solenoid malfunctions, it may fail to engage the reverse gear mechanism properly. This can lead to a delay in gear engagement or cause the gears to engage abruptly, resulting in a sudden jerk or jolt when shifting to reverse. The malfunctioning solenoid may also cause the transmission to slip between gears or fail to engage the intended gear altogether.

How to test?

To test shift solenoid, you need to check resistance across its terminals using a multimeter. The resistance should fall in the range specified for that shift solenoid.

You can watch the below youtube video to test the solenoids of an automatic transmission system:

5. Sticking Throttle Valve Makes Idle Speed Too High for Reverse Gear Activation

A throttle valve is a butterfly valve that opens and closes to control the amount of air that enters the engine.

The throttle valve is connected to the accelerator pedal by a cable (mechanical linkage) or an electronic sensor (called Accelerator Pedal Position Sensor) so that when you press the pedal, the valve opens more and allows more air to flow into the engine. This increases the engine speed and power output.

Conversely, when you release the pedal, the valve closes more and reduces the airflow into the engine. This decreases the engine speed and power output.

The throttle valve works together with the fuel injectors, which spray fuel into the intake manifold where it mixes with the air. The ratio of air and fuel is carefully controlled by the engine computer to achieve optimal combustion and performance. The ideal air-fuel ratio for most gasoline engines is 14.7:1, which means 14.7 parts of air for every one part of fuel.

Why does a sticking throttle valve cause car jerk when shifting to reverse?

Before shifting to reverse gear, we have to stop the car as shifting from drive to reverse while the vehicle is in motion can damage the transmission.

When your engine is idling, you expect the RPM to drop to around 800 RPM. If your throttle valve is sticking, it may not close properly and allow too much air to enter the engine.

As a result, it may cause the following problems:

  • Excessive wear and tear on the transmission and drivetrain components, as they have to cope with a sudden change in torque and direction.
  • Difficulty in engaging or disengaging the reverse gear, as the synchronizers have to overcome a higher rotational difference between the input and output shafts.
  • A loud clunk or bang noise from the transmission or differential, as they are subjected to a shock load.
  • A harsh jerk or lurch from the car, as the wheels are forced to spin in the opposite direction.

Why throttle valve becomes sticky?

A sticking throttle valve can be caused by various factors, such as:

  • Dirt, carbon deposits, or oil residue buildup on the valve or inside the throttle body.
  • Wear and tear on the valve or its hinges, springs, or seals.
  • Damage or corrosion on the cable that connects the pedal to the valve.

Manually move the throttle plate back and forth to ensure it moves smoothly without any sticking or hesitation. If you notice any resistance or uneven movement, it could indicate a problem with the throttle body mechanism. 

How to fix?

Use a throttle body cleaner and a soft brush or rag to gently clean the throttle body and remove any buildup.

6. Bad Engine or Transmission Mounts

bad engine mounts

Engine mounts are designed to hold the engine securely in place while also reducing the transmission of vibrations and noise to the vehicle’s cabin.

They are typically made of rubber or a combination of rubber and metal, which allows for some flexibility while maintaining stability. Engine mounts are strategically positioned to support the engine’s weight and counteract the forces generated during acceleration, deceleration, and cornering. 

Transmission mounts serve a similar purpose but are specifically designed to support the transmission system. They help secure the transmission to the vehicle’s chassis, ensuring that it remains in the correct position while also minimizing vibrations and movements.

Like engine mounts, transmission mounts are usually made of rubber or a rubber-metal combination for optimal performance. 

When engine or transmission mounts become worn or damaged, they lose their ability to effectively absorb vibrations and movements. This can lead to excessive engine or transmission movement, causing jerky shifts when engaging reverse gear

Why do they become bad?

Engine or transmission mounts become bad due to following reasons:

  • Age and mileage: Over time, the rubber or metal parts of the mounts can deteriorate due to exposure to heat, cold, moisture, oil, and dirt. This can make them lose their elasticity and strength, resulting in cracks, tears, or breaks.
  • Accidents or collisions: A major impact or force can cause the mounts to bend, deform, or shear off. This can happen in a crash, a pothole, a curb, or a speed bump.

How to test them?

To perform this test, you will need an assistant. With the engine running and the parking brake engaged, have your assistant shift the transmission from park to drive and then to reverse multiple times. Keep pressing down the gas pedal during this test.

Observe the engine’s movement during each gear shift. If there is significant movement, it suggests a worn-out mount.

If you are still uncertain about the condition of your mounts, you can perform a road test. During the test drive, pay close attention to any unusual noises, vibrations, or engine movements, especially when the vehicle goes over potholes.

For a visual test, you can do following steps:

  • Perform a Loose Bolt Check: Conduct a thorough examination of the motor and transmission mounts to identify any bolts that may be loose. The presence of loose bolts might indicate that the mount has experienced significant wear and should be substituted.
  • Check the Condition of the Rubber: Inspect the rubber components of the motor and transmission mounts carefully to detect any instances of cracks or tears. If such damage is found, it will be necessary to replace the rubber.
  • Evaluate the Mounting Bracket: Examine the mounting bracket associated with the motor and transmission mounts to identify any indications of wear or damage. The presence of wear or damage on the mounting bracket could be an indication that the mount itself has deteriorated and requires replacement.

Bonus Read: Car shakes at idle but smooths out when driving

7. Bad CV Joint

damaged CV joint

CV joints are designed with a flexible, rubber boot that surrounds the joint and keeps it lubricated. Inside the boot, there are ball bearings that allow for smooth rotation. 

CV joint allows for the transfer of power while accommodating the up-and-down motion of the suspension system. This flexibility is essential in maintaining a consistent velocity as the wheels move up and down, ensuring a smooth and comfortable ride.

When you shift your car into reverse, you are changing the direction of rotation of the wheels and the transmission. This means that the CV joints have to adjust to the opposite angle and speed of rotation.

If the CV joints are worn or damaged, they may not be able to smoothly accommodate this change and may bind or lock up momentarily. This can cause a sudden jerk or clunk as the joint snaps into place.

How to know if CV joint is damaged?

The CV joint is protected by a rubber boot, which keeps dirt and moisture out. If you notice any cracks, tears, or leaks in the boot, it is likely that the joint has been compromised.

The CV joint boot is designed to protect the joint from dirt, water, and other debris. However, if the boot becomes damaged or torn, these contaminants can enter the joint and cause damage. Dirt and water can mix with the grease and create a grinding paste that wears down the joint’s surfaces. Once the joint is compromised, it can no longer function properly. 

To learn more about CV joints, how they connect the differential to wheels, and how they are damaged, you can write my guide: can a CV joint damage transmission.

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