What is the reason for sudden abnormal noise when shifting from P to R gear when starting the car?
3 Answers
The reasons for sudden abnormal noise when shifting from P to R gear when starting the car are as follows: Gear shifting mechanism noise: The car's gear shifting structure consists of the gear lever, cables, gear selection and shifting structure, shift fork, and synchronizer. The noise from these parts is relatively small. Transmission noise: Long-term use of transmission oil can lead to sludge buildup, increasing the wear of friction plates and other components. Wear in these parts can cause malfunctions and abnormal noise. If the noise during gear shifting is small and comes from near the gear lever, it is normal noise from the gear shifting mechanism. If the gear shifting produces a 'clicking' sound, it is caused by gear impact failure in the transmission.
I think this situation is most commonly caused by transmission issues, such as a stuck lock-up solenoid valve failing to properly activate the torque converter, or insufficient or deteriorated transmission fluid leading to poor lubrication, which can result in abnormal noises when shifting to R gear. The sound might be a 'click' or 'hum', which can be quite alarming. If not addressed promptly, it can accelerate internal transmission wear, ultimately leading to exorbitant repair costs. I recommend starting with a simple check: after starting the car, listen for persistent abnormal noises while idling in each gear, and also check if the transmission fluid level is normal. Driving habits are also crucial—avoid shifting too hastily and ensure the car comes to a complete stop before changing gears. Safety first—if the abnormal noise occurs frequently, it's best to visit a professional repair shop immediately for a diagnostic tool check. Don't wait for a minor issue to become a major problem, as it not only damages the car but also compromises driving safety.
I was quite anxious when I encountered this issue last time. There was sudden noise when shifting from P to R gear, and the mechanic said it might be due to a faulty solenoid valve or sensor. It could also be caused by weak battery power leading to unstable voltage supply, or loose transmission components causing abnormal sounds. Additionally, aged or insufficient transmission fluid can cause this because dirty oil provides inadequate lubrication. I tried shifting more slowly myself, avoiding sudden movements, and the noise reduced somewhat. But I still went ahead to add new fluid and found the situation improved significantly. I recommend checking your battery condition and fluid levels, and performing regular maintenance to prevent carbon buildup issues. Drive smoothly and avoid gear shifts on slopes. If the abnormal noise persists, consult a professional immediately to prevent permanent damage.
