What is the reason for the car not moving when shifting to D gear in cold conditions but functioning normally when warm?
3 Answers
Introduction to the reasons why the car doesn't move when shifting to D gear in cold conditions but functions normally when warm: The issue is caused by faults in components such as the clutch, torque converter (torque drum), and solenoid valves. Severe wear or burning of the internal friction plates or other components within the clutch leads to poor engagement of the entire automatic transmission, resulting in a "short circuit" in power transmission. This prevents the gear from receiving driving force, causing a temporary loss of gear. Below are the related explanations: 1. After the engine starts, it generates a significant amount of power. The torque converter in the automatic transmission inputs this power into the transmission, which is then distributed to various gears through different types of clutches within the transmission, allowing the car to drive normally. 2. Severe wear or burning of the internal friction plates or other components within the clutch leads to poor engagement of the entire automatic transmission, resulting in a "short circuit" in power transmission. This prevents the gear from receiving driving force. 3. Additionally, if the internal oil temperature is too low or too high, the automatic transmission's computer cannot read and identify it, and thus cannot send commands to the gear switch and other electromechanical modules, causing the car to remain immobile.
I've been driving automatic transmission cars for ten years, and when encountering the issue of the car not moving when shifting to D gear in cold conditions, it's usually because the transmission fluid is too viscous at low temperatures. When the fluid is cold, its flowability is poor, and the pump can't quickly build enough pressure to engage the clutch, causing the car not to move; however, once the car warms up and the fluid thins, everything returns to normal. This is common in older vehicles or extremely cold weather. Check if the transmission fluid level is normal, and it's recommended to use full synthetic oil to improve low-temperature performance. Regularly change the fluid during routine maintenance to avoid impurity buildup. If the problem disappears after warming up the engine for a few minutes, it's a normal phenomenon; otherwise, there might be internal valve blockage or torque converter wear, and you should have it checked at a repair shop to avoid affecting driving safety.
As an automotive repair enthusiast, I analyze that there are two main reasons for a car not moving when shifting to D gear while cold: first, the viscosity of automatic transmission fluid increases at low temperatures, slowing down the hydraulic system's operation, preventing the oil pump from generating timely pressure to lock the torque converter; second, control system issues such as faulty temperature sensors sending incorrect signals to the ECU, delaying gear shifts. After the car warms up and the oil temperature rises, normal operation resumes. Preventive measures include selecting transmission fluid with good low-temperature performance and maintaining regular replacement intervals. Also, check if the fluid is clean to prevent filter clogging. Do not ignore this issue, as it may lead to transmission damage. Early intervention is recommended; seek professional diagnosis.
