1. Cable Issues:
* Shift Cable Adjustment: The shift cable might be out of adjustment, preventing the transmission from shifting properly. This is the easiest and cheapest thing to check. Inspect the cable for kinks, breaks, or rust. A slightly loose cable may be adjusted; however, if it's broken or severely corroded, replacement is necessary.
* Shift Cable Linkage: The linkage connecting the shifter to the transmission could be bent, broken, or disconnected. Carefully inspect this linkage for any damage.
2. Transmission Problems:
* Internal Transmission Failure: This is the most serious and potentially expensive problem. Internal problems within the transmission itself, such as broken gears, worn synchronizers, or low fluid, can cause it to stick in first gear. This often manifests with other symptoms like grinding, difficulty shifting, or slipping.
* Low Transmission Fluid: Check your transmission fluid level. Low fluid can cause many transmission problems, including difficulty shifting. Important: Check the fluid level with the engine running and warmed up, according to the specifications in your owner's manual. The fluid should be bright red; dark, burnt-smelling fluid indicates serious problems.
3. Other Possibilities:
* Shift Interlock: Some Cavaliers have a shift interlock that prevents shifting out of park unless the brake pedal is pressed. If this is malfunctioning, it could indirectly cause the problem.
* Electrical Issues (less common): In rare cases, electrical problems within the shift mechanism could cause issues, but this is less likely.
Troubleshooting Steps:
1. Check Transmission Fluid: This is the first and most important step. Low or bad fluid is a common cause of many transmission problems.
2. Inspect Shift Cable and Linkage: Carefully examine the shift cable for damage and check the linkage for proper connection and movement. Pay close attention to the connection points at both the shifter and the transmission.
3. Try Rocking the Car: Gently rock the car back and forth. Sometimes, a slight shift in position can help free a stuck gear. Be careful and use caution to avoid injury.
4. Manual Shift Attempt (If Safe): If the car is stopped in a safe location and you're comfortable doing so, *carefully* attempt to manually shift the transmission (if equipped with a manual option). This could help identify if the issue is within the transmission or the linkage.
5. Professional Inspection: If you've checked the above and the problem persists, take your Cavalier to a qualified mechanic for a professional diagnosis. A transmission problem can be costly to repair, so getting a proper diagnosis is crucial before undertaking repairs.
Important Safety Note: Never attempt to force a gear shift. This can cause further damage to your transmission. If your Cavalier is stuck in first gear and you cannot safely move it, call a tow truck.
