I have a 97 5,2 b2500 that I love for my service van, thing is a tank. however. I can constantly hear a rattling coming from what sounds like the tensioner area whenever I am going uphill or am under load. I am not over GVRW and I am not running anything aftermarket or out of the ordinary for it.

Yes, I replaced the tensioner, and the pulely (twice)

Am I hearing it echo from somewhere else because it almost sounds static like ping but not softer (if that makes sense)

belt is new and all pulleys are in good shape.

 

Check the wear indicator stops on the tensioner. If they're touching or even close to touching that is the source of the noise.