* Low Transmission Fluid: This is the first and easiest thing to check. Low fluid level can cause all sorts of shifting problems. Check the fluid level with the engine running and warmed up (follow the instructions in your owner's manual carefully, as incorrect procedure can lead to inaccurate readings). Low fluid might indicate a leak, which needs addressing urgently. Also, check the fluid's condition; it should be bright red and clear, not brown, burnt, or smelling burnt.
* Faulty Transmission Solenoid(s): The transmission uses solenoids to control fluid flow to the different clutch packs, enabling shifting. A faulty solenoid (or multiple solenoids) can prevent proper shifting. These are relatively inexpensive parts, but require some mechanical knowledge to replace.
* Transmission Valve Body Problems: The valve body houses the solenoids and various valves that control fluid pressure. Worn or damaged valves or passages within the valve body can disrupt the shifting process. This usually requires a professional rebuild or replacement.
* Worn Clutch Packs or Bands: The internal components of the transmission, including clutch packs and bands, wear out over time. If these are worn, they might not engage properly, causing slipping or a failure to shift. This typically requires a transmission rebuild or replacement.
* Torque Converter Issues: The torque converter connects the engine to the transmission. Problems within the torque converter can interfere with shifting, although this is less common as a cause of just 2-3 shift failure.
* Speed Sensor Problems: An inaccurate reading from the vehicle speed sensor can confuse the transmission's computer, leading to improper shifting.
* Transmission Computer (PCM) Problems: While less likely, a fault within the Powertrain Control Module (PCM) which controls the transmission could also be the issue. This usually requires diagnostic testing by a mechanic.
* Wiring Issues: Problems with the wiring harness connecting the transmission to the PCM can cause intermittent or complete shifting failures.
Troubleshooting Steps:
1. Check the transmission fluid level and condition. This is the absolute first step.
2. Have the transmission codes scanned: A professional mechanic can use a scan tool to read any diagnostic trouble codes (DTCs) stored in the PCM. These codes will often pinpoint the problem.
3. Listen for unusual noises: A whining, grinding, or clunking noise from the transmission can indicate internal problems.
Important Note: Trying to diagnose and repair transmission problems yourself can be challenging and potentially dangerous. If you're not comfortable working on cars, it's best to take your Taurus to a qualified mechanic for diagnosis and repair. Ignoring transmission problems can lead to significant and costly damage.
