I have to replace the "center muffler" section of the exhaust system because both pipes adjacent to the connection to the "catalytic converter" section are so badly corroded they have large holes in them. I cannot get the car to pass state inspection. I guess the system is original. I managed to get the rear two sections separated from the cat section (and now the car sounds like a speed boat ). Now I am faced with carefully separating the rear muffler section from the center muffler section.

I have loosened the clamps but the (slotted) overlapping pipes appear to have "welded" themselves together.

Has anyone faced a similar plight?

Any ideas on what I can do to separate the two sections, because liberal amounts of WD-40 penetrating oil has had no effect?

I don't want to damage the rear muffler section because it appears to be very expensive to replace. The center muffler was bad enough!

Any advice would be appreciated.