How to Drain the Transmission Fluid on a 2006 Chevy Trailblazer. You need to drain the automatic transmission fluid in the 2006 Chevy Trailblazer at 30,000 miles or 30 months. Once you drain the fluid, you need to immediately add four quarts of fresh transmission fluid through the filler neck in the engine compartment. General Motors recommends using Dexron VI transmission fluid for this particular year and model.
Raise the truck with a floor jack and support it on jack stands. Place a drain pan that can hold at least eight quarts underneath the transmission-fluid pan.
Disconnect the shift linkage that partially covers the transmission-pan bolts at one side of the pan--disconnect its cable end from the ball stud and then remove the bolts for the cable's bracket using your wrench.
Remove the bolts along the flange of the transmission-fluid pan using a flare-nut or similar wrench. Leave the bolts at each of the corners alone until you have removed the others, then remove the bolts in the front corners..
Pry the pan loose slowly and carefully at the front end of the pan using a flat screwdriver. Tilt the pan and pour the transmission fluid into the drain pan.
Disconnect the remaining bolts on the transmission pan and remove the pan from the transmission.
Clean the inner surface of the transmission pan with solvent and blow it dry using compressed air. Clean away all traces of the old gasket and sealant from the transmission surface with the solvent.
Pull down on the transmission filter located inside the transmission valve body and remove it. Install a new filter in the transmission with a new seal, which is often pre-installed on replacement filters.
Reinstall the transmission pan--with a new gasket--onto the transmission and install the bolts. Tighten each bolt with your wrench a little bit at a time until every bolt is at 97 inch-pounds. Reconnect the shift linkage with its bolts and cable.