Two problems related to axle shaft seal have been reported for the 2002 Chevrolet Trailblazer. The most recently reported issues are listed below.
I noticed oil on my driveway. I took my Trailblazer to the dealership. They told me that the front axle shaft was leaking fluid and that it was going to cost $800 to replace a couple of seals in the pinion and the gear box.
Right front outer shaft seal failure. This is a light truck/SUV that seldom sees use off of a paved road. The "right front outer shaft seal" should not be failing at 57,326 miles. "goodwill warranty" covered portion of replacement cost.