That being said, if you're determined to proceed (at your own risk!), here's a general overview. This is not a complete guide and should not be substituted for a professional repair manual specific to your vehicle's transmission type (4L60E is common but not guaranteed).
Methods:
There are two primary methods:
1. Power Flush (using a transmission flush machine): This is the most thorough method, but requires specialized equipment found at transmission shops. The machine pumps fresh fluid through the transmission, displacing the old fluid. This is generally the best option for getting the most contaminants out.
2. Drain and Fill (multiple times): This is a less thorough but simpler method (relatively). You repeatedly drain the transmission fluid, refill it, run the vehicle, and repeat the process several times. This gradually replaces the old fluid but doesn't clean the torque converter as effectively as a power flush.
General Steps (Drain and Fill Method - highly simplified):
1. Consult your owner's manual: Find the correct type and amount of transmission fluid for your Trailblazer. (Dexron III or equivalent is likely).
2. Locate the transmission pan: This is usually located underneath the vehicle.
3. Prepare for the job: Gather your tools: wrench or socket to remove the drain plug, drain pan, new transmission filter (if applicable - check your manual), funnel, new transmission fluid. Jack up the vehicle securely and use jack stands. Wear safety glasses and gloves.
4. Drain the fluid: Carefully remove the drain plug and let the fluid drain into the pan.
5. Replace the filter (if necessary): Some transmissions have an external filter; others have an internal one that's not easily replaceable without a complete transmission teardown.
6. Remove the transmission pan: This may require removing bolts and may involve some spillage.
7. Replace the gasket/seal on the pan.
8. Reinstall the transmission pan.
9. Refill the transmission: Add the specified amount of new transmission fluid through the dipstick tube or filler port (location varies by vehicle).
10. Run the engine: Run the engine to operating temperature, checking the fluid level periodically. Add more fluid as needed. Many recommend driving the vehicle for some time to circulate the new fluid before checking the level again.
11. Repeat steps 4-10 multiple times: This is crucial for effective fluid exchange, even with the drain and fill method. The number of times needed depends on how dirty the fluid was and how much you want to improve its cleanliness.
Important Considerations:
* Transmission type: The 2002 Trailblazer likely has a 4L60E transmission, but you MUST verify this. Procedures vary slightly between transmission types.
* Torque Converter: A power flush is much better at flushing the fluid within the torque converter. The drain and fill method affects it much less.
* Fluid level: Checking the fluid level incorrectly can lead to transmission damage. Follow the instructions in your owner's manual carefully.
* Professional help: If you're uncomfortable with any aspect of this process, take your vehicle to a qualified transmission shop. The cost of professional service is far less than the cost of repairing a damaged transmission.
This information is for general guidance only. Always consult a repair manual specific to your 2002 Chevy Trailblazer before attempting any transmission work. Improper procedure can lead to significant damage and expense.
