ORIGINAL: Rodney

The biggest problem with two piece mufflers failing (the ones with a long threaded rod from front to back holding them together) is not vibration. It is the fact that the thermal expansion of the long rod is quite different from the muffler body. This constant expansion/contraction effect from the heat of combustion then cooling off stretches the threaded rod and lets the junction become loose. There is no amount or type of sealing material that will correct this fault as it is just a poorly engineered design.