What causes the car to shake when in D gear?
2 Answers
The reasons for the car shaking when in D gear are as follows: Engine speed is too high: When the engine speed is too high during cold start, the torque converter transmits more power, resulting in greater impact force and more noticeable shaking when shifting into D gear. Brake not pressed firmly: At the moment of shifting, the engine power is directly transmitted to the wheels. If the brake is not pressed firmly, the wheels will move slightly when shifting into D gear, causing the car to suddenly move forward and creating a stronger shaking sensation. Brake released too early: This leads to abrupt power engagement. Without the limiting effect of the brake, the drive wheels suddenly receive power at the moment of gear engagement, causing the car to move forward directly and resulting in shaking.
I've encountered many cases of car shaking when in D gear. As an experienced mechanic, this is usually caused by engine ignition issues or transmission problems. The most common culprit is worn-out spark plugs causing ignition mismatch, making the engine shake at idle. Faulty ignition coils with unstable sparking can also be the reason. For transmission issues, worn torque converters are the primary cause - especially when stopped in D gear with high pressure, leading to uneven power delivery. Low or dirty transmission fluid causing insufficient lubrication can also trigger shaking. Don't overlook worn engine mounts either - they cushion engine vibrations, and broken mounts transmit vibrations directly to the frame. I suggest first checking spark plugs and fluid levels yourself - often just replacing spark plugs or topping up transmission fluid solves the problem. Leaving this issue unaddressed can damage engine or transmission components, increasing repair costs. Always inspect shaking issues immediately - don't wait until the check engine light comes on or the car won't move before taking action.
