When ever the a/c is on and the trans in D there is a loud rattle. It only happens when in D not P or N. The sound looks like is coming from the tensioner. The tensioner moves to the sound. Anyone had one fail early? I've only got 56k miles.
Now that I've had a chance to crawl around under it, it seems the noise is coming from the motor mount directly accross from the tensioner. I had someone rev the engine while in D and there was a loud scraping/rattle sound.
Hey @VegasGMC (and @youri), My Mazda CX9 is doing the same thing! ... only when in D and with the AC on. I believe this is because it puts the engine under more low rev stress which makes for more shaking / vibrations. Was your problem the tensioner itself or the motor mount?
