On a 2008 grand with the 3.7 engine is there a gasket at the flange where the muffler bolts to the cat pipe?Ive looked all over for diagrams but can only find stuff for wjs which have a totally different setup.The flange I got for the new muffler seems to have a rounded donut protrusion so maybe no gasket needed? advance auto lists an exhaust flange gasket but Im not sure. Im not ready to take the old one off yet but want to have everything Ill need to put the new one on ahead of time.