* Low Transmission Fluid: Check your transmission fluid level *immediately*. Low fluid is a common cause of shifting problems and can lead to serious transmission damage if ignored. Check the fluid level with the engine running and warmed up. The fluid should be reddish-pink and clean; dark brown or burnt smelling fluid indicates serious problems.
* Transmission Solenoids: These electronically controlled valves manage fluid flow within the transmission, directing it to engage different gears. A faulty solenoid can prevent the shift to third gear. This often requires professional diagnosis and replacement of the faulty solenoid(s).
* Transmission Valve Body: The valve body houses the solenoids and other internal components that control shifting. Problems within the valve body can cause various shifting issues, including the one you describe. Repair or replacement is usually a significant undertaking.
* Torque Converter: The torque converter connects the engine to the transmission. Problems with the torque converter can also affect shifting.
* Transmission Control Module (TCM): This computer controls the transmission's operation. A faulty TCM can cause various shifting problems. This often requires professional diagnosis using specialized tools.
* Wiring Harness Issues: A short circuit, broken wire, or corroded connection in the wiring harness supplying the TCM or solenoids can prevent proper shifting.
* Low Line Pressure: A problem with the transmission pump could result in insufficient pressure to shift gears properly.
What NOT to do:
* Don't continue driving the car extensively in this condition. Forcing the transmission to stay in second gear will likely cause more damage and increase repair costs significantly.
What to do:
1. Check the transmission fluid level and condition as described above. This is the absolute first step.
2. Have the car professionally diagnosed by a transmission specialist or a reputable mechanic. They have the tools and expertise to diagnose the problem accurately and determine the best course of action. A simple visual inspection and fluid check won't provide a complete diagnosis.
3. Get multiple quotes before authorizing repairs. Transmission repairs can be expensive.
Ignoring the problem will almost certainly lead to a more costly repair or even a complete transmission replacement. Professional help is your best option.
