Possible Causes:
* Incorrect Fluid: Canadian Tire might have used the wrong type of transmission fluid for your 2004 Sebring LX 2.4L. Automatic transmissions are very specific about the fluid type. Using the incorrect fluid can cause significant problems, including slipping and shuddering.
* Fluid Level: Even if the correct fluid was used, an incorrect fluid level (too high or too low) can cause issues.
* Transmission Problems (Pre-existing): The transmission may have already had internal problems (worn clutches, valve body issues, etc.) that the service didn't fix but made more apparent due to the fresh fluid highlighting the existing damage. The fresh fluid might have cleaned out some debris, revealing the underlying issue.
* Filter Installation: While less likely, the transmission filter might not have been installed correctly.
* Other Issues (Less Likely): While less probable given the timing, other issues like a faulty speed sensor or a problem with the torque converter could also contribute.
What to Do:
1. Return to Canadian Tire: Go back to Canadian Tire immediately. Explain the problem in detail and show them the receipt. They might have a warranty on the service, and they should investigate whether they used the correct fluid and procedure. This is the first and most important step.
2. Independent Transmission Specialist: If Canadian Tire is unhelpful or unable to resolve the issue, take your car to a reputable independent transmission specialist. They can perform a proper diagnosis to pinpoint the exact cause. They'll likely need to:
* Inspect the Transmission Fluid: Check the color, smell, and level of the fluid.
* Perform a Road Test: To observe the symptoms firsthand.
* Diagnostic Scan: Use a scan tool to check for any transmission-related fault codes.
* Internal Inspection (potentially): This might require dropping the transmission pan to inspect for worn parts or damage.
3. Avoid High Speeds: Don't drive the car at high speeds until the problem is resolved. Continuing to drive with a damaged transmission can cause further damage and potentially lead to a complete transmission failure.
Important Note: A transmission repair can be expensive. Getting a second opinion from a different mechanic *before* committing to major repairs is always a good idea. The independent specialist can provide a better estimate of the cost of repair or replacement.
