A few months ago, I had my harmonic balancer replaced due to it vibrating. The guy that did it showed me the old balancer, and sure enough it was coming apart. And sure enough, the new one was working nice and smooth. So....about a month ago I noticed that the new one is already shaking again. It smooths out when you rev the engine up past 2,000 rpms though. On top of that, about a week or so ago it's started making a whining at me like a ball bearing starting to go out or hard rubber on smooth metal...would that be the main seal? I haven't really taken an engine apart that far for a few years now and am rusty on a lot of things. I'm kinda confused as to what would cause this(the harmonic balancer vibrating and the noise). Anybody have any ideas? The guy that owns the place said something about a sleeve needing to get replaced on the crankshaft, but I dunno. It just doesn't sound right.