What Causes an Automatic Transmission Car Not to Move When Shifting to Reverse and Accelerating?
2 Answers
Clutch slippage or insufficient power. Below are the relevant explanations: 1. Main manifestations of clutch slippage: Clutch slippage is primarily characterized by the vehicle's inability to increase speed in response to the engine's rising RPM during acceleration. The engine's power cannot be fully transmitted to the driving wheels, resulting in weak driving performance, especially noticeable when going uphill. 2. Insufficient power: If the car does not accelerate when the throttle is pressed, attention should also be directed to the engine. The source of power comes from fuel combustion, and the engine is responsible for supplying fuel and converting chemical energy into mechanical energy. Therefore, when the car exhibits weak acceleration or slow speed increase, the engine system should be a key focus for inspection.
I have some experience dealing with the issue of automatic transmission cars not moving in reverse. The most common cause is a failed brake light switch—the transmission locks the reverse function if the brake isn't pressed. Additionally, a worn or loose neutral safety switch can interfere with signal transmission, resulting in ineffective gear shifting. Low or contaminated transmission fluid reduces hydraulic pressure, affecting power transfer, especially noticeable during warm or cold starts. Internal component failures are another major cause, such as slipping clutches or stuck valves inside the torque converter, often accompanied by noise or vibration. Although rare, misjudgments by the electronic control unit or sensor malfunctions can also occur. I recommend car owners first check if any dashboard warning lights are on, try shifting into Park and then Reverse once more, and ensure the brake is fully depressed. If that doesn't work, check the fluid level—it should be bright red and clear. Top up if it's low; if the problem persists, replace the switch, which costs around ten dollars. Avoid forcing the throttle to prevent damaging the transmission core.
