Workhorse W22, Chevy 8.1l exhaust rattle/noise

With the exhaust system cold, slide under the MH and hit the catalytic converter with your hand or a block of wood. If it sounds like a can full of marbles, . . . . you need a new converter. If no noise, try the same thing with all the other components of the exhaust system. Eventually you will find the source of the rattle. Check all your exhaust hangers and heat shields too.

Chum lee