1. Transmission Issues (Most Likely):
* Low Transmission Fluid: Check your transmission fluid level. It's crucial for proper operation. Low fluid can lead to slipping and inability to engage gears. If low, add the correct type of transmission fluid (check your owner's manual). *However, if the fluid is low, there's likely a leak somewhere that needs attention. Don't just add fluid and drive away.*
* Dirty or Worn Transmission Fluid: Even if the level is correct, dirty or old fluid can cause problems. A transmission fluid change might help, but a more serious internal issue could still be present.
* Internal Transmission Problems: This is the most likely serious problem. Worn clutch packs, broken bands, or other internal damage are common causes of this symptom in older vehicles. This usually requires professional repair or transmission replacement.
* Transmission Solenoid Problems: These electrical components control gear shifting. A faulty solenoid can prevent the transmission from shifting into drive or reverse. Diagnosis requires a scan tool.
* Transmission Linkage Problems: (Less common on automatics) Though less common in an automatic, a problem with the linkage could prevent proper engagement.
2. Other Potential Causes:
* Shift Cable Adjustment: (Less common on automatics) Improper adjustment of the shift cable (if applicable) could prevent the transmission from selecting the correct gear.
* Park/Neutral Safety Switch: This switch prevents the car from starting unless the gear selector is in Park or Neutral. A faulty switch can prevent starting *and* gear selection.
* Battery/Electrical Issues: A weak battery or other electrical problems can affect the operation of the transmission. Try jumping the car to see if this helps (but don't repeatedly jump if it fails, as it's unlikely to be the root cause).
* Computer/PCM Issues: The Powertrain Control Module (PCM) controls many aspects of the engine and transmission. A faulty PCM can cause various malfunctions. This would require a scan tool.
Troubleshooting Steps:
1. Check Transmission Fluid: This is the first thing you should do. Check the level and condition of the fluid.
2. Check the Battery: Make sure your battery is sufficiently charged.
3. Listen for Unusual Noises: When trying to shift, listen carefully for any unusual grinding, whining, or banging noises from the transmission.
4. Try Starting in Neutral: If you can shift into neutral, try starting the car. This checks the park/neutral safety switch.
5. Get a Professional Diagnosis: If you've checked the fluid and battery and are still having problems, it's time to take your Taurus to a qualified mechanic or transmission specialist. They'll have the tools and expertise to diagnose the issue accurately. A scan tool can often reveal transmission codes that pinpoint the problem.
Do not attempt to drive the car if it's not shifting properly. Continued use could cause further damage to the transmission. The cost of ignoring the problem will likely greatly outweigh the cost of a proper diagnosis and repair.
