I'm trying to figure out a ticking or tapping noise from the K5. It is rpm related, so it gets quicker when I rev the engine. I can hear it loudly at idle. I can't really hear it once the truck gets going down the road or if I rev it to a certain level and beyond. Just real annoying and makes the truck sound like crap but there has not been a decrease in performance. I just replaced the fan clutch because I thought that was it but it wasn't. So, I was told by a couple of people that it might be the harmonic balancer. What do you guys think? I thought those things were suppose to last forever. Stats: 87 350 FI 4 bolt main SM465 3.42 rear end all stock about 83K original miles.