What causes the abnormal noise when stepping on the brake in P gear?
3 Answers
The reasons for abnormal noise when stepping on the brake in P gear are as follows: Sound from the gear lock: When you step on the brake, the gear lock is released, producing a clicking sound. Parking in P gear without engaging the handbrake: If parked on a slope, the car may still move forward or backward until the parking lock pawl engages to secure the vehicle. Once locked, the vehicle's braking relies on the pawl. When moving the vehicle out of P gear, the pawl lock is first released, and the sound you hear is the unlocking noise. Brake pad backplate length deviation: You can step on the brake, shift into drive gear, let the car move slightly, then shift into reverse gear, let it move slightly again, and shift back into drive gear to see if the noise occurs each time. If it does, it indicates excessive brake pad clearance. Additionally, inspect the rear brake system to ensure all bolts are properly installed and tightened.
I've been driving for over 20 years, and it's quite common to hear unusual noises when pressing the brake in P gear. At first, I thought there was an issue with the brakes, but after inspection, I found the brake pads weren't worn out yet. Upon closer consideration, the noise might come from small parts in the transmission, like the locking pin—when you press the brake, the increased pressure can cause it to squeak if it's rusty or loose. Alternatively, worn components in the brake system, such as insufficient lubrication in the pedal linkage, can also create noise. The sound tends to be louder during cold starts due to thermal expansion and contraction of the parts. My advice is not to ignore this issue. Try this first: With the engine running, press the brake and listen. If the noise only occurs in P gear, it's likely a transmission problem, requiring a visit to the repair shop for lubrication or part replacement. If the noise happens every time you brake, then the brake discs need immediate inspection. Safety comes first—distractions while driving can be dangerous. Regular maintenance can help avoid these headaches.
I think the noise when pressing the brake in P gear may be related to multiple systems. The most common cause is the brake components: worn brake pads can produce squealing sounds when they reach a certain level of wear, or warped brake rotors can cause irregular vibrations. Another reason could be the transmission locking mechanism—pressing the brake in P gear triggers an interlock, and if the pins are worn or dirty, it may produce a rattling sound. I've noticed this kind of abnormal noise occurs more frequently in older cars, possibly due to a lack of lubrication and maintenance. You might start with a simple diagnosis: place your hand on the gear lever while pressing the brake to feel if the vibration increases. If it does, it likely points to a transmission issue. It's best not to delay, as minor faults can escalate. Take it to a professional shop for a tool-based inspection—replacing small parts or making adjustments can often solve the problem. Pay attention to changes in unusual noises during daily driving; they're often the car's way of reminding you that something needs attention.
