Why doesn't an automatic transmission car move when shifted to R gear without pressing the accelerator?

[OWalter]

An automatic transmission car not moving when the accelerator is pressed may be due to the clutch not fully engaging; the handbrake not being released; the gear being stuck and not fully engaged; or wear and tear on the clutch disc. Automatic transmission gear positions: Generally, an automatic transmission has 6 to 7 gear positions, arranged in order from front to back. They are P (Park), R (Reverse), N (Neutral), D (Drive), and some Drive positions include D, 3, 2, and 1 gears. Some models have only three Drive positions (D, 2, 1). If equipped with a four-speed transmission, there may also be an overdrive selection switch (O/D) to engage the overdrive gear. Correct driving method for automatic transmission cars: Start the engine with the gear shift lever in the P position, and you must press the brake pedal to shift from P to other gear positions. When starting, push the gear shift lever to a lower gear position (i.e., 2 or 1, some may also have 3), and after the speed increases to a certain level, shift to D for normal driving. If cruising at high speed on a highway, you can use the O/D gear to save fuel.

[VonMaddox]

I once encountered this issue - the car wouldn't move when shifting to R gear while reversing in the garage, which made me sweat with anxiety. This situation is quite common, mainly due to insufficient engine torque at idle speed being unable to propel the vehicle. When an automatic transmission vehicle is in reverse gear, the engine runs at low RPM with minimal power output, especially on flat roads or slight slopes. After checking my car, I found the handbrake was fully released with no obstructions; applying slight throttle made it move. This isn't a malfunction - many vehicles are designed this way to prevent accidental movement. However, if this persists, it might indicate transmission aging, torque converter wear, or improperly set idle speed. I recommend gently pressing the accelerator (avoid sudden bursts to prevent component damage). For safety, always check surroundings for people/obstacles before shifting gears. Regular maintenance like transmission fluid changes can prevent issues, and newer car designs are more intelligent. Overall, don't worry - just follow proper operating procedures.

[AidenAnn]

When I first started driving, I often encountered this issue: the car wouldn't move when I shifted to R gear, and I thought it was broken. Later, I learned that in an automatic transmission car, when reversing, if you don't press the accelerator, the engine only runs at low speed and doesn't have enough power to move the car. This is completely normal, especially on flat ground. Check if the handbrake is still engaged or if there's any obstruction to the tires. If everything seems fine, just gently press the accelerator. However, if this happens frequently, it might indicate a transmission issue, such as insufficient oil pressure or a sensor malfunction. I must remind you to operate carefully when reversing: always check the rearview mirror first and ensure it's safe before proceeding. Don't worry; all beginners go through this. It's safer to have a professional technician inspect it. In terms of maintenance, paying attention to your car's condition every month can help reduce problems. After learning more about driving, I now handle such situations calmly.

[OMila]

As someone who enjoys studying mechanics, let me explain why the car doesn't move when shifting to R gear without pressing the accelerator. The principle is that the engine's idle output power is low, and the transmission has poor conversion efficiency when reversing, possibly requiring additional thrust. The torque converter has limited power transmission at low speeds, and thermal losses become more noticeable. For fuel efficiency and quietness, the idle speed is set low in design. If it occasionally doesn't move, gently pressing the accelerator will suffice; if it persistently doesn't move, check the engine management unit or if the transmission fluid is dirty. Modern cars have optimized this system, while older cars are more prone to issues. I recommend maintaining good car condition to avoid neglecting potential wear. Simple maintenance can resolve most situations.