No need to drop the trans to check the flywheel bolts. Just rock the frywheel back and forth while holding the crank. You would be suprized what kind of noise the bolts make. A automatic trans flywheel wheel or flex plate will be a higher pitched knock them a heavy manual trans clutch flywheel combination. Then engine will not idle smooth on its own, it needs the weight of the flywheel to smooth it out. If the bolts are loose, you will hear it banging against them as its running. A loose balancer will make a similer noisy. Joe
