Here's a breakdown of the options and what's involved:
1. Multiple Drain-and-Fill Method (Recommended for DIY):
This method is safer and less likely to cause problems than a power flush. It requires several drain-and-fill cycles over a period of time (e.g., days or even weeks) to gradually replace most of the ATF.
* What you'll need: New ATF (check your owner's manual for the correct type and quantity), a drain pan, a wrench or socket to remove the drain plug on the transmission pan, a new transmission filter (highly recommended), and a funnel.
* Procedure:
1. Warm up the transmission: Drive the car for 10-15 minutes to warm the ATF.
2. Locate the transmission pan: This is usually on the bottom of the transmission.
3. Position the drain pan: Place the drain pan under the transmission pan.
4. Remove the drain plug: Carefully remove the drain plug, letting the old ATF drain into the pan.
5. Remove the transmission pan: Once drained, remove the transmission pan bolts (be careful, some ATF might still spill). Replace the transmission filter while the pan is off. Clean the pan thoroughly (magnetic drain plug will likely need cleaning too).
6. Reinstall the transmission pan: Replace the transmission pan gasket (a new one is recommended) and reinstall the pan.
7. Replace the drain plug: Tighten the drain plug to the manufacturer's specifications.
8. Refill the transmission: Add new ATF through the dipstick tube until it reaches the correct level (check your owner's manual).
9. Repeat: Drive the car for 50-100 miles, then repeat steps 1-8. You may need to do this 2-3 times to significantly reduce the amount of old ATF.
2. Power Flush Method (Not recommended for DIY):
This method uses a machine to force new ATF through the transmission, pushing out the old fluid. This is quicker but carries a greater risk of damaging the transmission if done incorrectly. Only take your vehicle to a reputable transmission shop for this service. A bad power flush can cause transmission damage due to the pressure and potential for contaminants to be dislodged.
Important Considerations:
* ATF Type: Use the exact type of ATF specified in your owner's manual. Using the wrong type can severely damage your transmission.
* Level: Check the ATF level carefully after each drain-and-fill cycle, following the instructions in your owner's manual.
* Transmission Condition: If your transmission is already showing signs of problems (slipping, harsh shifts, etc.), a fluid change might not solve the underlying issue. A professional diagnosis is necessary.
In summary: For a 2002 Buick Century, the multiple drain-and-fill method is the safer and recommended approach for a DIYer. If you are not comfortable working on your car, take it to a qualified mechanic or transmission specialist. A power flush is best left to professionals. Always consult your owner's manual for specific instructions and recommendations for your vehicle.
