* Low Transmission Fluid: This is the most common and easiest to check. Low fluid leads to insufficient lubrication and can cause harsh shifts and jerking. Check the fluid level (with the engine running and warm) and ensure it's within the proper range on the dipstick. Also, inspect the fluid's condition; it should be reddish-pink and clear, not dark brown or burnt smelling.
* Dirty or Worn Transmission Fluid: Even if the level is correct, old, contaminated fluid can cause problems. The fluid degrades over time and loses its lubricating properties, leading to harsh shifting. A transmission fluid and filter change is often a good first step.
* Worn-out Transmission Solenoids or Valves: These electrical components control fluid flow within the transmission. If they're malfunctioning or sticking, it can cause erratic shifting and jerking. Diagnosis requires a scan tool capable of reading transmission codes.
* Failing Torque Converter: The torque converter is a critical component that transfers power from the engine to the transmission. If it's worn or slipping, it can cause jerking, especially during acceleration or shifts. This is a more expensive repair.
* Worn Clutch Packs or Bands: Inside the transmission are clutch packs and bands that engage to change gears. Wear and tear can cause slippage and jerky shifts. This usually requires a transmission rebuild or replacement.
* Problems with the Valve Body: The valve body houses the solenoids and other hydraulic components. Internal problems within the valve body can cause shifting issues.
* Computer/PCM Issues: The Powertrain Control Module (PCM) controls the transmission's operation. A faulty PCM can send incorrect signals, resulting in jerking. A diagnostic scan is necessary to check for PCM codes.
* Shift Linkage Problems (manual transmissions only): If your Mustang has a manual transmission, problems with the shift linkage can cause imprecise shifting and jerky movements.
To diagnose the problem:
1. Check the transmission fluid level and condition. This is the easiest and cheapest thing to do first.
2. Have the vehicle scanned for diagnostic trouble codes (DTCs). An OBD-II scanner can read codes that might pinpoint the problem. A professional mechanic will have more advanced diagnostic tools.
3. Consult a reputable mechanic. They have the experience and tools to properly diagnose and repair transmission problems. Trying to fix a transmission yourself can be costly and dangerous if done incorrectly.
Ignoring a jerking transmission can lead to more serious and expensive damage. It's best to address the issue promptly.
