* Low Transmission Fluid: This is the most common and hopefully least expensive issue. Check your transmission fluid level (consult your owner's manual for location and proper checking procedure). Low fluid can cause serious damage, so don't drive it until you've checked.
* Transmission Fluid Problems: The fluid might be old, dirty, or burnt. This can affect the transmission's ability to shift properly. A fluid change and filter replacement might be necessary.
* Broken or Worn Transmission Components: Internal parts like clutches, bands, or gears could be worn, broken, or malfunctioning. This often requires a significant repair or even a transmission rebuild or replacement. This is a more serious and expensive problem.
* Shift Linkage or Cable Issues: While less likely given you can engage park and reverse, a problem with the linkage or cable that connects the shifter to the transmission could prevent the car from engaging the forward gears.
* Solenoid Problems (Automatic Transmission): Automatic transmissions use solenoids to control shifting. A faulty solenoid can prevent the transmission from engaging the forward gears.
* Valve Body Issues (Automatic Transmission): Problems within the valve body, which controls fluid flow within the transmission, can also lead to shifting problems.
* Computer/Sensor Problems (Automatic Transmission): A malfunctioning transmission control module (TCM) or related sensors could be preventing the transmission from shifting into forward gears. This often requires diagnostic testing.
What you should NOT do:
* Don't keep trying to force the gears: This could cause further damage.
* Don't drive the car: Driving with a malfunctioning transmission can cause significant and costly damage.
What you SHOULD do:
1. Check the transmission fluid level and condition: This is the first and easiest thing to check.
2. Have the car towed to a qualified mechanic: They can properly diagnose the problem using diagnostic equipment and determine the necessary repairs. Trying to fix this yourself is generally not recommended unless you have significant automotive experience.
Ignoring the problem will almost certainly lead to more expensive repairs down the line. Get it checked out by a professional as soon as possible.
