很多車主會有這樣的經歷，就是原地踩住剎車，當檔位從P檔切換到R檔時會產生沖擊感，然后再從R檔切換到P檔時，會聽到變速箱內部產生敲擊聲。在P檔和D檔之間切換也有類似情況。如果在原地反復在P檔與R檔之間切換，沖擊和噪音會更明顯。這是怎么回事呢?下面有個官方解釋，有興趣的了解一下。
Many car owners have the experience of holding on to the brakes in place, creating a sense of impact when shifting gears from P to R, and then shifting gears from R to P, hearing a knock inside the transmission. A similar situation exists when switching between P and D gears. If you repeatedly switch between P and R gears in place, the impact and noise will be more noticeable. What's going on here? Below is an official explanation for those interested in learning about it.
官方解釋
Official interpretation
當在D檔停車時，如果變速箱內部的應力沒有在N檔釋放就直接掛入P檔，那么在從P檔掛入R檔時駐車鎖的釋放就會使輸出軸突然釋放應力而帶動車輛沖擊-下。
When parking in D gear, if the stress inside the transmission is directly shifted into P gear without being released in N gear, the release of the parking lock when shifting from P gear to R gear will cause the output shaft to suddenly release the stress and drive the vehicle down.
當掛入R檔并等待3秒以后，同樣因為有驅動力的原因，使得輸出軸會反向旋轉一個角度，使得駐車鎖塊與棘輪齒壞能對應，此時再掛入P檔時由于驅動力的消失，輸出軸因失去驅動力而回轉，駐車鎖由回位彈簧的驅動而入位時就會產生-個金屬敲擊聲。
After shifting into R gear and waiting for 3 seconds, due to the same driving force, the output shaft will rotate reversely by an angle, causing the parking lock block to correspond to the ratchet teeth to fail. At this time, when shifting into P gear again, due to the disappearance of the driving force, the output shaft will rotate due to the loss of driving force, and a metal knocking sound will occur when the parking lock is driven into position by the return spring.
所以，這種沖擊和噪音是由變速箱的產品特性、產品結構，再加上不當的操作弓|起的，此問題不需要維修。
Therefore, this impact and noise are caused by the product characteristics and structure of the gearbox, coupled with improper operation. This problem does not require maintenance.
應對措施
Countermeasures
濟南奔馳汽車維修人員提醒，在原地快速而頻繁的在D檔與P檔或者R檔與P檔之間切換檔位是不正常的操作。停車時在N檔松開剎車，釋放一下應力，然后再掛入P檔車輛將不會產生擊。
Jinan Benz car maintenance personnel reminded that it is abnormal to quickly and frequently switch gears between D and P gears or R and P gears in place. When parking, releasing the brake in N gear, releasing the stress, and then engaging the vehicle in P gear will not cause a shock.
這是正常現象，不會對變速箱硬件有任何影響也不會影響變速箱的使用性能及壽命。
This is a normal phenomenon and will not have any impact on the transmission hardware or affect the service performance and life of the transmission.
Although this problem is a normal phenomenon, shifting shock and noise are indeed one of the common failures of gearboxes. Therefore, when encountering this problem, everyone should be cautious and determine whether it is due to their own operating skills. If not, they should go to the maintenance shop as soon as possible to have a look. For more relevant content, please visit our website http://m.nanofluidizer.com consulting service
