* Transmission fluid level is low. If the transmission fluid level is too low, the transmission will not be able to properly engage the gears, which can cause the car to move when it's in gear.
* Transmission filter is clogged. A clogged transmission filter can restrict the flow of transmission fluid, which can also cause the car to move when it's in gear.
* Faulty transmission valve body. The transmission valve body controls the flow of transmission fluid, and a faulty valve body can cause the car to move when it's in gear.
* Faulty torque converter. The torque converter transmits power from the engine to the transmission, and a faulty torque converter can cause the car to move when it's in gear.
If your car is moving when in gear, it's important to take it to a qualified mechanic to have it diagnosed and repaired.
