很多车主会有这样的经历，就是原地踩住刹车，当档位从P档切换到R档时会产生冲击感，然后再从R档切换到P档时，会听到变速箱内部产生敲击声。在P档和D档之间切换也有类似情况。如果在原地反复在P档与R档之间切换，冲击和噪音会更明显。这是怎么回事呢?下面有个解释，有兴趣的了解一下。
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.
解释
Official interpretation
当在D档停车时，如果变速箱内部的应力没有在N档释放就直接挂入P档，那么在从P档挂入R档时驻车锁的释放就会使输出轴突然释放应力而带动车辆冲击-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.
当挂入R档并等待3秒以后，同样因为有驱动力的原因，使得输出轴会反向旋转一个角度，使得驻车锁块与棘轮齿坏能对应，此时再挂入P档时由于驱动力的消失，输出轴因失去驱动力而回转，驻车锁由回位弹簧的驱动而入位时就会产生-个金属敲击声。
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，这种冲击和噪音是由变速箱的产品特性、产品结构，再加上不当的操作弓|起的，此问题不需要维修。
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.
应对措施
Countermeasures
济南奔驰汽车维修人员提醒，在原地快速而频繁的在D档与P档或者R档与P档之间切换档位是不正常的操作。停车时在N档松开刹车，释放一下应力，然后再挂入P档车辆将不会产生击。
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.
这是正常现象，不会对变速箱硬件有任何影响也不会影响变速箱的使用性能及寿命。
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://www.lutongqixiu.com consulting service
