My sister just bought a 2001 trailblazer 250 yesterday. I went with her to help her break it in properly. I noticed it made the noise at slower speeds (haven't got full throttle yet)when excellerating. The dealer says that is normal. My buddies did the same thing, even after many upgraded. The rubbing noise is mostlikly the clutch cover. If you go through water when the engine and clutch cover is very hot, it make the plastic cover warp. Been there, done that.

Steve

 

i gave a little miss info. It does it whenever I let off the gas or it may be that I can't hear it do it when giving the gasbecause of the pipe. Anyway thanks for the help.