What causes the shaking when braking in D gear?
3 Answers
When the car is in D gear, the engine's power can be transmitted to the transmission, and the transmission can transfer the power to the wheels. However, with the brakes applied, the wheels cannot rotate, which results in the body shaking. There are three common types of automatic transmissions in automatic cars: 1. AT transmission: The most mature and widely used automatic transmission. The AT transmission can be referred to as a torque converter transmission, which connects to the engine via a torque converter. Inside the AT transmission, there are many planetary gears, and this type of transmission relies on these planetary gears to change speed and torque. 2. CVT transmission: A transmission with a relatively simple internal structure. This transmission only has two cone pulleys and a steel belt inside. The steel belt can move on the cone pulleys, allowing the transmission to change speed and torque. 3. Dual-clutch transmission: A product developed based on manual transmissions. This type of transmission simply adds an extra set of clutches and a shift control mechanism compared to a manual transmission. One set of clutches in the dual-clutch transmission controls the odd-numbered gears, while the other set controls the even-numbered gears. Dual-clutch transmissions offer fast shifting speeds and relatively high transmission efficiency.
Last time I drove an automatic car, I encountered this situation. When I stepped on the brake in D gear, the car shook like it was dancing. After checking, I found that the throttle was too dirty, and carbon deposits blocked the airflow. Unstable engine idling can cause shaking, and it could also be due to aging spark plugs causing poor ignition. By the way, it's recommended to check the engine mounts—if they're aged or deformed, they can amplify the vibration. If you usually do the work yourself, start by disassembling and cleaning the throttle and replacing the spark plugs. You can buy the tools from Taobao. If that doesn’t help, check the transmission fluid color—if it’s black or has impurities, it’s time to change it to prevent excessive internal wear in the transmission, which can cause jerking. It’s best to perform regular maintenance to reduce such issues.
The shaking is particularly noticeable when stopping at a red light, making me nervous while driving. When the engine mount rubber pads age, deform, or crack, the vehicle's buffering function fails, leading to severe shaking. Additionally, uneven or rusted brake discs can exacerbate the sensation of wobbling, especially when the engine is still running slightly in D gear. Once, when I went for repairs, the mechanic used a multimeter to detect unstable line voltage affecting the idle control module. In short, safety issues should not be ignored. When the shaking is severe, pull over immediately, turn off the engine to avoid overheating damage, and send it to a professional shop as soon as possible for a comprehensive inspection of the transmission and power systems.
