If you own a Chevy or GMC Duramax, there is a "ticking time bomb" under your hood that you need to know about. From the factory, the harmonic balancer is held in place by a small alignment pin that is notorious for shearing. When that pin fails, the balancer spins freely, which frequently leads to a broken crankshaft  and a total engine loss. We recently had a customer in our Yuma, Arizona garage who chose to get ahead of the curve by installing a harmonic balancer keyway pin