Car owner Mr. Huang: my car has been driving 25000 kilometers, I recently found that the cold car started to the hot car, when the engine number reaches 1000, when the brake is tightened, the resistance to the D gear is bigger and the R gear has a greater impact. What is the reason for this? Expert visits: automatic models, theoretically hanging will have a sense of impact, D block and R block. If the impact is different, it may be caused by the damage level of the front and rear shock pad and the internal fault of the gearbox. In addition, the larger impact may be caused by too high engine speed, and the power transmission of the transmission is determined by the engine speed. Mr. Zhao: in recent days, when my car started, I felt a clicking noise near the A column, especially in the bumpy road. After the heat, the sound disappeared. What is the reason? Is it so low that the temperature is too low? Expert visits: if the sound is related to the temperature change, it should be the cold noise of the engine valve, which is increasing with the mileage of the car (5-10 kilometers), and it is also the abnormal sound in the normal natural wear process. In addition, according to what Mr. Zhao said, the bumpy road section is very loud. It may be caused by loose parts near the A column, which is independent of temperature.