An exhaust gas aftertreatment system for a vehicle includes a cylindrical inner shell, a cylindrical outer shell, an inner end cap, a metal mounting member, and an outer end cap. The inner shell is configured to guide exhaust gas. The outer shell forms a first gap to the inner shell. The inner end cap encloses an open end of the outer shell. The inner end cap includes a first axially-extending lip. The inner end cap is fixed to the inner shell. The outer end cap is fixed to the inner end cap. The outer end cap includes a second axially-extending lip. The outer end cap and the inner end cap cooperate to encapsulate the mounting member. The first axially-extending lip is sandwiched between the outer shell and the second axially-extending lip.