Can you help me with a problem the Dealer can't diagnose?

First truck i drove that had "clunk" around corners was due to leaf spring being broken. That sucked. I also recall a "cab clunk" on other trucks when braking hard or tight turns especially under load. I BELIEVE it was diagnosed as bushing that supports the cab. I just remember being told, "It's fine, just run it." I think that's an industry motto...