What Causes the Sound When Braking in Reverse Gear for Automatic Transmission?
3 Answers
The sound that occurs when pressing the brake pedal while reversing is likely coming from the brake disc and pads. This issue is usually caused by the hardened surface layer of the brake pads. Additionally, it could be due to the chamfering effect that develops after prolonged use of the brake pads. The solution is to have the brake pads resurfaced at a 4S repair shop. Handbrake Operating Principle: The handbrake, technically referred to as an auxiliary brake, operates differently from the main braking system. It uses a steel cable connected to the rear brake shoes to apply braking force to the vehicle. Prolonged use of the handbrake can cause the steel cable to undergo plastic deformation. Since this deformation is irreversible, long-term use will reduce its effectiveness and increase the handbrake's travel distance. The handbrake system also includes a return spring. When the handbrake is engaged, the spring stretches; when released, it returns to its original length. Over time, this spring can also deform with extended use. The Necessity of Proper Brake Usage: The handbrake is a frequently used system. Proper and correct usage ensures smoother operation in the future, extends its adjustment intervals, and reduces maintenance and replacement costs.
I've experienced this situation several times. Every time I reverse and step on the brake, I hear abnormal noises, which is quite annoying. Generally, this sound may come from worn brake pads. In automatic transmissions, when reversing, the engine's power reverses, increasing the pressure on the friction between the brake disc and pads. If the pads are worn thin, they're more likely to make a clunking noise. Additionally, the suspension system undergoes significant load changes when reversing, which can also cause noise, such as loose springs or rusted, oil-deprived wheel bearings. Don't overlook transmission issues either; aging mechanical components during reverse gear shifts can amplify sounds. For a simple at-home check: first, park the car securely, then gently rock the wheels while stepping on the brake. If you feel looseness, it might be a bearing problem. Regular maintenance of brake pads and wheel bearings, checked every 20,000 kilometers, can prevent major repairs. If the noise is frequent and accompanied by dragging, take your car to a repair shop immediately for inspection—safety first. Delaying could lead to dangerous wheel detachment.
Last week when I was reversing my car to go back to my hometown, I suddenly heard a squeaking sound when I stepped on the brake, which almost made me steer wildly in panic. Later, I figured out that the sound is often simple—it could be due to dust accumulation on the brake discs from the brake system, causing more friction when reversing; or the wheel hubs might have rusted in humid weather, making noise when stuck during low-speed operation. When an automatic transmission is shifted into reverse, the torque distribution changes, which might loosen the drive shaft connection points and amplify the noise. I suggest you check it yourself first: start the car, lightly press the brake a few times, and try reversing again. If the sound doesn’t disappear, take it for repairs. I’ve worked on similar cases at a 4S shop—most are minor issues that can be fixed by replacing brake components for a few hundred yuan, but ignoring it could lead to bearing replacement costing over a thousand. Remember, safety comes first—if you hear unusual noises, stop reversing and inspect the issue.
