What Causes the Abnormal Noise When Braking in an Automatic Transmission Car?

[SanKhloe]

Automatic transmission cars may produce abnormal noises when braking due to normal ABS activation or electronic linkage. Below are the detailed explanations: Normal ABS Activation: The working process of ABS is actually a cycle of locking and releasing, keeping the vehicle in a state of critical lock-up with intermittent rolling. When you press the brake pedal hard enough to trigger the ABS, it may produce a clunking sound, which is normal. In this case, simply press the brake pedal firmly to the floor. Gear Shift 'Clunk' Sound When Braking in an Automatic Transmission Car: If you hear a 'clunk' sound between the transmission and the gear lever when pressing the brake pedal, the main cause may be the electronic linkage between the braking system and the automatic transmission. Pressing the brake activates the transmission solenoid valve, producing the 'clunk' sound. This serves as a safety reminder, requiring you to press the gear lever lock button to shift gears.

[OJasmine]

I've encountered the issue of strange noises when stepping on the brakes in an automatic transmission car, mainly indicating the braking system needs inspection. The most common cause is worn brake pads or foreign material contamination, such as small stones getting mixed in, which can produce a sharp grinding noise, especially noticeable at low speeds. Another reason could be uneven brake rotors or rust buildup, for example after driving in rainy conditions where accumulated water causes rust, resulting in squeaking sounds when braking. Additionally, improperly retracting or stuck brake calipers may cause irregular metallic clanking noises. It's best to regularly check brake rotor thickness - replacement is recommended if it falls below 3mm; meanwhile, keep wheels clean to minimize gravel accumulation. If the noise persists, it's advisable to promptly visit a repair shop for inspection. Don't wait until safety is compromised to take action, as brake issues are critical. Delayed treatment might lead to more expensive repair costs.

[Ramirez]

When I drive and press the brakes, there's noise, and I feel it's mostly due to maintenance neglect. Worn or deformed brake pads are the root cause—over time, the material becomes brittle, producing squeaking sounds, especially noticeable when starting the vehicle. Another factor is loose wiring or components, like unfastened screws, which can rattle and produce clicking sounds during braking. Additionally, weather plays a significant role, as cold temperatures cause materials to contract, increasing friction noise. I make it a habit to inspect the brake system every 5,000 kilometers, including cleaning dust and applying grease to the joints. If unusual noises occur, I prioritize replacing the brake pads or discs—it's a low-cost measure that can prevent dangerous situations like sudden brake failure. During daily driving, I also avoid prolonged partial braking to reduce overheating and noise. Safety comes first—never overlook these small warning signs.

[Jeremy]

I've dealt with brake squealing issues before, and the common cause is brake pad problems. If the pad material is too thin or has hard spots causing friction, it produces a screeching sound, especially noticeable during low-speed stops. Another possibility is an uneven rotor surface – even slight warping can create resonance noises. It's recommended to regularly check pad thickness; at least 5mm is considered safe. If there's significant rust buildup, simple sanding can often alleviate the issue. Additionally, improper bedding-in of new brake pads during installation may cause noise – they need time to adapt. Don't delay addressing this problem; either perform a simple DIY inspection of pad condition or visit a professional shop to resolve it, preventing potential roadside emergencies.