Why Does an Automatic Transmission Car Make Noise When Shifting Gears?

[DeJanelle]

Here are the reasons why an automatic transmission car makes noise when shifting gears: Shifting gears when the car is not completely stopped: If you shift to P gear before the car comes to a complete stop, the P gear lock hook inside the transmission will hit the gear, making a clicking sound. Incorrect operation sequence when parking on a slope: For automatic transmissions, the P gear relies on the lock hook to secure the gear and keep the car stationary. When parking on a slope, you should first engage the handbrake and then shift to P gear, allowing the handbrake to bear the downward force of the vehicle. Worn transmission gears: The transmission is a precision component, and the gears best reflect its precision. However, due to their tight meshing, wear is inevitable. Over time, larger gaps will form between the gear teeth, causing noise when shifting gears.

[OCecilia]

Last time when I shifted gears in my car, I also heard a clicking sound. The mechanic said it might be due to the transmission oil not being changed for too long, leading to insufficient lubrication. Deteriorated oil increases friction between the gears. Additionally, aging of the gearshift mechanism is a common cause, especially for cars that have been driven for seven or eight years. When the rubber bushings inside wear out, the increased gaps can cause abnormal noises. Another issue could be a broken engine mount, which can misalign the transmission, causing the gears to not align properly during shifting, resulting in noise. The most troublesome problem is internal transmission issues, such as stuck valve bodies or planetary gear teeth grinding, which require a major overhaul. I suggest first checking the condition of the fluid. If the oil is black and has a burnt smell, change it immediately. If that doesn’t help, use a diagnostic tool to check for error codes. Don’t force it to drive, as damaging the gears will make repairs even more expensive.

[Nunes]

My newly purchased used car always makes a clunking sound when shifting into D gear. A friend suggested first checking if the floor mat is interfering with the brake pedal, as some full-coverage mats can obstruct the shift cable, causing the gear lever to stick and produce abnormal noises. Another possibility is unstable battery voltage—when the battery is low while parked, the shift motor may lack sufficient power to rotate smoothly, resulting in a clicking sound. Try jump-starting to see if there's any improvement. If the car is over 5 years old, pay special attention to the transmission mount bushings. Worn-out rubber reduces damping effectiveness, allowing shift shocks to transfer to the chassis and create noise. I once tried revving the engine in neutral before shifting—if there’s a jerky sensation due to poor RPM matching, it’s likely the TCU program needs an update. During routine maintenance, remind the technician to check the transmission fluid level, as low fluid can lead to insufficient oil pressure.

[LillianLee]

Gear shifting noises depend on the specific situation. If it occurs when parking, it's mostly due to loose shift cables, and if it's noticeable during cold starts, the transmission oil temperature sensor should be checked. If there's jerking and noise during gear shifts while driving, it's likely the clutch plate is burnt, especially common in dual-clutch models. I once repaired a car that had gear impact sounds every time it shifted from P to R, and it turned out to be a broken detent spring, which required dismantling the transmission to fix. For cars with paddle shifters that make noise, the wear level of the shift motor carbon brushes should also be inspected. A simple way to diagnose: if the noise increases when the AC is on or when turning the steering wheel, it's usually due to engine load fluctuations affecting transmission oil pressure. Remember, if the noise persists for more than ten days, don't delay—small issues can turn into costly transmission overhauls.

[SanKira]

I was terrified when I encountered strange noises while shifting gears. Later, I learned that automatic transmission cars parked on a slope might produce gear-locking sounds when shifting to P, but hearing noises on flat roads is abnormal. For girls with less physical strength, if the gearshift becomes unusually heavy and accompanied by creaking sounds, it's likely due to insufficient lubrication in the shifting mechanism. It's also important to develop the habit of pulling the handbrake first before shifting to P when parking, as directly shifting to P can put excessive stress on the transmission gears. Additionally, cars with modified underbody guards should be cautious—there have been cases where deformed guards pressed against the shift cable, causing noises. My best friend's car made a clicking noise every time she shifted to reverse, and it turned out to be a short circuit in the reverse light wiring interfering with the transmission computer. I recommend that girls driving should first note the frequency of abnormal sounds—whether they occur at the first startup each day or randomly—to describe the issue more accurately to the technician.

[VonTravis]

After noticing abnormal noises when shifting gears, I first ruled out basic issues by ensuring the brake was fully depressed before shifting and that the floor mat wasn't obstructing the mechanism. When the car was warm, shifting gears had noticeable delays and grinding sounds, leading me to suspect a clogged valve body oil passage. Upon removing the oil pan, metal debris was found on the filter screen. Additionally, a blocked transmission oil cooler can cause excessively high oil temperatures, and when the oil film breaks, the gears grind dry, resulting in noise. For CVT models, belt drive noises often indicate a high probability of belt slippage. Those who have modified their intake or exhaust systems should be aware that exhaust resonance can sometimes transmit to the transmission, causing harmonic noises. Recently, I observed a new phenomenon: when remotely starting the car and immediately shifting gears, the abnormal noise is pronounced, but it disappears if I wait for the idle speed to drop before shifting. This is related to the idle speed matching logic.