Two problems related to transmission noise have been reported for the 2003 Chevrolet Trailblazer. The most recently reported issues are listed below.
My 03 ext first transmission went out with just over 65k and then 16mo. Later at 80k went out again. No help from gm. I have owned a 99 blazer and 02 Trailblazer with no real issues however this 03 has had numerous from cracked gas tank to catalytic converter going out as well as now having loud engine noise!.
I bought a used 2003 chevy Trailblazer 2 months ago, now I' having over $1500 worth of transmission work done to it! after coming downhill on a busy highway, as I started up, a noise came from under my feet. I lost power and every time I gave it gas, that noise returned. Almost ran over by the heavy traffic speeding down the hill, was finally able to pull onto the dangerous shoulder. Shop said shell broke apart and went into trans. Shop said he has made a good living on these transmissions!!!. . . And replaces them with a much better, thicker, stronger "spline" in them. Who has to get killed before they switch over to these better aftermarket pieces?.