Car Jerks When Changing Gears: Causes Along with Solution

It can be frustrating and even scary when your car jerks or lurches when changing gears. 

This sudden noise can occur by various issues in the transmission or clutch system and can indicate larger mechanical problems if left without a repair. 

In this comprehensive guide, we’ll explore all the reasons your car jerks when shifting gears and provide solutions to overcome those.

Rare Causes For the Sound

The Clutch System

• The clutch is made up of a friction disc and pressure plate that connect the engine’s crankshaft to the transmission input shaft.

• When the clutch disc is on active mode, its friction material comes into contact with both the flywheel and the pressure plate.

• When the clutch pedal is down, the release bearing pushes the pressure plate away from the clutch disk to break the contact between these spinning components.

• This allows the gear selector to move without transmitting power to the drivetrain when it’s between gears.

• When the clutch pedal is released, spring pressure brings the flywheel, clutch disk and pressure plate back into direct contact to reconnect the engine power to the transmission.

• So, if the clutch system functions with sever issues, that could lead to jerking noises when changing gears.

Worn Clutch Components

• As time passes, the friction material on the clutch disc can wear down or become contaminated with oil.

• The pressure plate can also become warped or lose its spring tension under this condition.

• This allows some clutch slippage during acceleration when changing gears.

• A worn clutch disc or pressure plate leads to noticeable jerking motions as the transmission struggles to find the right gear.

Clutch Cable Issues

• With manual transmissions, the clutch pedal pulls on a mechanical cable that actuates the release bearing.

• Sticky clutch cables prevent full clutch disengagement when shifting gears.

• Therefore as a result, frayed or binding cables also lead to jerky clutch engagement.

• Replacing the defective clutch cables are needed to restore the smooth gear changes.

Low Clutch Hydraulic Fluid

• Many clutches operates the hydraulically via master and slave cylinders instead of cables.

• Over time, the fluid can leak out from the clutch hydraulic system.

• Due to this reason, low levels may prevents a smooth actuation of the clutch when changing gears by resulting in a sound.

• Usually checking for leaks and topping up the clutch fluid resolves this issue.

Synchronizers and Gear Alignment

• Synchronizers (or synchro rings) are cone-shaped collars on the transmission shaft.

• They have brass teeth that mesh with the gear’s teeth before the collar locks it to the shaft.

• This allows the speeds of the loose gear and shaft to reach equilibrium at first.

• Over time, the brass teeth on the synchro rings get rounded off from friction.

• This prevents them from adequately synchronizing the gear and shaft speeds when shifting gears.

• Attempting to force a rough shift causes abrupt jerking motions as well.

Synchronizer Operation Issues

• Synchro rings can also stick due to contaminated fluid or improper adjustments.

• This delays their response time in matching the gear and shaft speeds.

• Slow synchronizer response may also leads to some jerky gear engagement will in operation.

Mounts and Motor Brackets

• The engine and mounts and motor brackets secure the transmission. 

• If these components become loose, cracked or worn out, it allows too much movement of the powertrain when shifting gears. 

• This also leads to jerking motions.

Common Causes of the Sound When Shifting Gears Along With Solutions

Now that you know how the transmission works, here are the most common root issues that can make your car jerk when changing gears:

Low Transmission Fluid

• One of the easiest issues to detect is low automatic transmission fluid. 

• When the fluid level drops too low, it stops lubricating components properly during gear changes. 

• Check the dipstick after parking on a flat surface when the engine is warm. Top up the fluid if needed.

Faulty Sensors

• Modern automatic transmissions rely on an array of sensors and solenoids that controls the fluid pressure, torque and shift points. 

• Faulty speed, throttle position or shift solenoid sensors will confuse the computer by leading to abrupt any gear changes. 

• Diagnostic trouble codes usually point to specific sensors when faulty.

Slipping Transmission Bands

• Most automatic transmissions use bands and clutches to engage the proper gear. 

• Worn friction bands starts to slip under acceleration when changing gears. 

• If so, you’ll feel a jerking lunge as the transmission struggles to apply power. 

• To overcome this issue, Inspect and replace any worn bands to restore a smooth shifting.

Ignition Misfires

• An engine misfiring as you accelerate during gears changes will make the transmission abruptly engage and disengage. 

• It’s caused by ignition issues like faulty spark plugs, bad wiring or poor fuel supply in the engine cylinders. 

• Make sure to diagnose and fix the misfires to stop any transmission jerking.

Computer Glitches

• Sometimes abnormal transmission operation comes down to computer software issues. 

• Various sensor data feeds information to the powertrain computer. 

• Bad sensor inputs combined with software glitches may leads to jerky computer-controlled shifts. 

• Resetting the computer through an OBDII scanner often resolves the jerky shifting behaviour if no mechanical problems exist.

Drivetrain and Engine Concerns

Loose or Damaged Mounts

• The engine and the transmission are secured by mounts made of rubber or hydraulic fluid.

• Over time, the rubber can crack, or the fluid can leak.

• This allows excessive engine movement when changing between gears.

• If mounts are loose or failing, it can cause a noticeable jerking sensation.

• Replacing any damaged mounts restores the proper drivetrain alignment and reduces any gear shift jerking.

Alignment Issues

• The engine, transmission, driveshaft and rear axle needs to be properly aligned in order to enhance the performance.

• If the powertrain becomes misaligned, the gear train may bind or stick during shifts.

• Trouble shifting gears smoothly can indicate an underlying alignment issue.

• Adjusting the positioning or replacing any warped components may be needed to address the drivetrain misalignment problems.

Ignition System Defects

• Issues like worn spark plugs, faulty wiring, bad sensors can also cause engine misfires.

• When cylinders misfire as the transmission shifts, it leads to abrupt engagement or disengagement of gears.

• Then the transmission controller overcompensates for the engine power loss by  creating jerky shifts.
• Fixing ignition problems may reduces the variability in engine RPM/power and leads to smoother gear changes

Preventing Future Issues

Regular Inspections and Maintenance

• Transmission fluid, filters, seals, and valves require periodic replacement.

• Catching worn parts like bands, clutches, and bearings early may prevents bigger issues later.

• Inspect the engine and the drivetrain mounts for cracking or deterioration.

• Diagnose any sensor calibration, or computer errors before they advance.

• Well-maintained components have a much lower risk of abrupt in jerky gear shifts.

Noticing Early Signs of Problems

• Learn to recognize any subtle symptoms that indicates any drivetrain troubles.

• Pay attention to new vibrations, slippage, sticky shifts, and abnormal noises.

• Addressing minor transmission problems promptly may reduces the likelihood of catastrophic failure.

• Minor drivetrain fixes are much cheaper than a complete overhaul or rebuild.

Following the Manufacturer Service Schedule

• The owner’s manual details the repair intervals for fluid changes, and adjustments.

• Stricter intervals may be required for heavy-duty or high-mileage vehicles.

• Deviating from recommended services may often accelerates any wear and tear.

• Closely following the factory guidelines optimizes any transmission operation and smooth shifting.

Frequently Asked Questions About Car Jerks When Changing Gears

Q: Is it normal for my car to jerk when changing gears?

A: An occasional small jerk when the vehicle is cold or warming up is normal. But consistent jerking, lurching or hard shifting when changing gears means your transmission likely has an issue that needs diagnosis.

Q: Are gear shift jerks are a damage issue to the transmission?

A: Over time, the abrupt force from gear shift jerks can degrade internal transmission components by leading to more slippage and wear. It’s best to diagnose and repair the underlying issue before any permanent damage occurs.