* Transmission problems: This is a very common cause. Issues could include:
* Broken or slipping clutch (manual transmission): The clutch engages the engine to the transmission, allowing power to reach the wheels. If it's broken or slipping, power won't transfer effectively.
* Faulty transmission components (automatic transmission): Many internal parts are needed for an automatic transmission to function. A broken component like a band, solenoid, or planetary gear can prevent forward motion.
* Low transmission fluid: Insufficient fluid can cause overheating and damage, leading to the inability to move forward.
* Engine problems: If the engine isn't running properly or producing enough power, the car won't move. This could be due to:
* Lack of fuel: Simple, but easily overlooked.
* Spark plug issues: If the spark plugs aren't firing correctly, the engine won't combust fuel efficiently.
* Fuel delivery problems: A blocked fuel filter or fuel pump failure can prevent fuel from reaching the engine.
* Drivetrain problems: This covers the components transferring power from the engine to the wheels:
* Broken driveshaft: A driveshaft connects the transmission to the differential. A break here will prevent forward motion.
* Differential problems: The differential allows the wheels to rotate at different speeds when cornering. A problem here will impact the ability to move.
* Axle problems: Axles transfer power from the differential to the wheels. A broken axle prevents forward movement.
* Brake problems: A stuck parking brake or a problem with the service brakes can prevent forward movement.
* Computer/Electrical problems: Modern cars rely heavily on computers. A malfunctioning computer module, especially the transmission control module (TCM), can prevent the car from shifting into drive.
* Shift linkage/selector problems (manual transmission): Issues with the linkage or selector itself can prevent the car from entering the forward gear.
It's crucial to have a mechanic diagnose the specific problem. Simply stating that a car only goes in reverse doesn't pinpoint the cause, as many different systems could be at fault.
