I have a 2003 Blazer ZR2 and whenever I drive it on the highway for an extended period of time a I seem to get a persistant squeking coming from the rear every time I hit a a bump. Does anyone have any suggestions where it maybe coming from?

 

it is probably your springs there is plastic shoes i call them in between each leaf check them they might be worn or gone they are only $1-2 a piece

 

I had the same problem and it ended up being the bushings for the shock absorbers. Have some body bounce on the rear end and spray some WD-40 to verify before you spend any money.