* Low Transmission Fluid: This is the first and easiest thing to check. Low fluid level leads to inadequate lubrication and can cause harsh shifting and jerking. Check the fluid level with the engine running and warmed up. If low, add the correct type of transmission fluid (consult your owner's manual). *Low fluid also often indicates a leak, which needs addressing*.
* Dirty or Worn Transmission Fluid: Even if the level is okay, old, dirty fluid can cause poor transmission performance. The fluid breaks down over time and loses its lubricating properties. A fluid change and filter replacement are recommended.
* Failing Torque Converter: The torque converter is responsible for smooth engagement between the engine and transmission. A worn or failing torque converter can cause harsh shifts and jerking. This is a more significant repair.
* Solenoid Problems: The transmission uses solenoids to control fluid flow. A faulty solenoid can cause erratic shifting. These are relatively inexpensive to replace but require some mechanical knowledge or professional assistance.
* Worn Clutch Packs or Bands: These components inside the transmission wear out over time. Worn clutch packs can cause slipping and jerking during acceleration. This is a major repair.
* Computer Issues (PCM/TCM): The Powertrain Control Module (PCM) or Transmission Control Module (TCM) can malfunction, leading to incorrect shifting commands. A diagnostic scan can reveal if this is the issue.
* Shift Linkage Problems (if applicable): While less common on automatics, a problem with the shift linkage could be a factor if it’s contributing to incorrect gear selection.
* Engine Problems: While less likely to cause a jerking *into* gear, problems with the engine itself, such as misfires or vacuum leaks, could contribute to a rough acceleration that *feels* like a transmission issue.
Troubleshooting Steps:
1. Check the transmission fluid level and condition. This is the easiest and cheapest first step.
2. Get a diagnostic scan: This will help pinpoint any electronic problems with the PCM, TCM, or solenoids. An OBD-II scanner can do this.
3. Listen for unusual noises: Grinding, whining, or banging sounds from the transmission indicate more significant internal problems.
Important Note: Ignoring transmission problems can lead to more extensive and costly repairs. If you're not comfortable working on the transmission yourself, take the vehicle to a qualified mechanic for diagnosis and repair. The 1995 Windstar transmission is known for potential issues, so professional help is often warranted.
