Alright, Lets see...I have a 02 Blazer LS....with about 68,000 miles on it....I noticed the other day when i had the heat and radio off(still can't figure out why both were off) but anyways....I was coasting on my road to about to make a turn and I hear a clicking sort of sound coming from the rear of my blazer, quicker as I speed up slower as I slow down....I cant really tell if its still there when i hit the gas, can't hear it over the engine....but i'm assuming its still there.....what are the possibilities of these symptoms i know theres not much info....if this were my 2000 Impala I would have said bad bearing....but not sure with this...

 

There isn't really much in the back of the truck that would make that noise. The only things that I can think off are your differential, bearings and u-joint. My guess would be your u-joint. Perhaps someone else in the forum that has more experience can share their opinion.