* Transmission Problems: This is the most common cause. Issues could include:
* Slipping clutch (manual transmission): The clutch isn't engaging properly, so the engine spins freely without transferring power to the transmission.
* Broken or damaged transmission components (automatic or manual): Internal parts like gears, bands, or clutches might be worn, broken, or malfunctioning.
* Low transmission fluid: Insufficient fluid can prevent proper lubrication and power transfer.
* Faulty torque converter (automatic transmission): The torque converter, which connects the engine to the transmission, might be failing to lock up properly.
* Driveshaft Problems:
* Broken driveshaft: A broken driveshaft prevents power from reaching the rear wheels (in rear-wheel drive vehicles) or all wheels (in some all-wheel-drive systems).
* Disconnected driveshaft: The driveshaft could be disconnected or improperly connected.
* Differential Problems:
* Locked differential: A seized or locked differential will prevent the wheels from turning.
* Broken differential components: Internal gears or components in the differential could be damaged.
* Wheel Problems:
* Parking brake engaged: This is a simple but easily overlooked cause.
* Seized wheel bearings: A seized wheel bearing will prevent the wheel from rotating.
* Tire problems: Though rare, a completely flat tire or a severely damaged tire can prevent movement.
* Other less common causes:
* Computer problems: In some cases, a faulty engine control unit (ECU) or other electronic components could be preventing power transfer.
* Incorrectly installed components: A recent repair could have resulted in something being installed improperly.
To diagnose the problem, you'll likely need a mechanic to inspect the vehicle. They can check the transmission fluid level, listen for unusual noises, and perform other diagnostic tests to pinpoint the exact cause. Ignoring the problem could lead to further damage and more expensive repairs.
