Possible Causes & Solutions (in order of increasing complexity & cost):
1. Low Transmission Fluid: This is the easiest and cheapest fix. Check your transmission fluid level (while the engine is running and warm) using the dipstick. If it's low, add the correct type of ATF (Automatic Transmission Fluid) specified in your owner's manual. Important: A significantly low level suggests a leak, which needs to be addressed.
2. Dirty or Contaminated Transmission Fluid: Old, dirty fluid loses its lubricating properties and can cause shudder. A transmission fluid and filter change is a relatively inexpensive fix, and often resolves the issue. This should be done with the correct type of ATF and following the procedures in your owner's manual or a reputable repair manual.
3. Torque Converter Problems: This is a more serious and costly issue. The torque converter itself might be failing, due to worn clutches, internal damage, or a faulty pump. Symptoms can include shudder, slipping, and harsh shifting. A full transmission rebuild or torque converter replacement might be necessary. This is typically done by a professional transmission shop.
4. Solenoid Issues: The transmission's solenoids control fluid flow. A faulty solenoid can cause erratic shifting and shudder. These are relatively inexpensive parts, but diagnosing which solenoid is faulty requires specialized equipment and knowledge. Again, a professional mechanic is usually required.
5. Valve Body Problems: The valve body manages fluid pressure and flow throughout the transmission. Worn or damaged valve body components can cause various transmission problems, including shudder. Repairing or replacing the valve body is a more complex and costly repair, typically requiring professional attention.
6. Transmission Cooler Issues: A clogged or malfunctioning transmission cooler can lead to overheating and fluid degradation, contributing to shudder. Check the transmission cooler lines for blockages or damage. Replacing the cooler might be necessary.
7. Other Transmission Problems: More severe internal transmission problems can also manifest as shudder. These can include worn clutches, bands, or planetary gear sets, ultimately requiring a major rebuild or replacement.
What to Do:
1. Start with the simplest: Check and top off the transmission fluid. If it's significantly low, find and fix the leak *before* doing anything else.
2. Consider a fluid and filter change: This is a relatively inexpensive preventative measure, and often resolves minor shudder issues.
3. Seek professional help: If the shudder persists after checking the fluid and changing the filter, it's time to take your Caravan to a reputable transmission specialist or mechanic. They have the tools and expertise to diagnose the problem accurately and recommend the appropriate repair. Ignoring the problem can lead to more extensive and costly damage.
Warning: Attempting major transmission repairs yourself without the proper knowledge and tools is strongly discouraged. You could cause further damage, increasing the repair cost significantly.
