I, too, have a Flowmaster 40 series. After I had my truck notched, I had to cut off my exhaust right before the notch. Well, I recently got the exhaust fixed..the only possible solution was to run it UNDER the axle. Don't worry, we left enough room for the axle to travel down, though. It was either that or run it out between the leaf springs and the frame. Anybody else done this? Am I crazy?