Muffler sounds like it has golf ball inside.
 

So my exhaust started to make a rattling sound about a week ago. I had it changed from rear duals out the rear to dual pipes out the passenger side in front of the tire right after I bought the truck 6 months ago. The muffler shop simply moved the exsisting flowmaster closer to the fornt of the truck and rerouted the exit pipes. When I first heard this rattle, I assumed that it was a loose hanger. I called my muffler shop, and they said bring it in and they would weld it back for free since it has only been five months since they rerouted it for me.

This morning I got under the truck with it running to try and figure out which hanger it was before I took it to the shop. All the hangers were tight and there were no broken welds at all. I have a flowmaster muffler on the truck. While the truck is idling, it sounds as if there is a golf ball or something rattling around inside it.

I know that there are chambers and fiberglass and what not inside the flowmaster mufflers that give it the aggressive tone and that they can go bad just like any other muffler. I am not sure when the flowmaster was installed, but I imagine the previous owner had it put on when the truck was new. My truck is an 05 but only has 45k on it so the muffler can't have any more miles than that.

Has anyone ever experienced this with a flowmaster muffler? My exit pipes are pretty short (about a foot and half from muffler exit to end of tip) and possibly someone could have put something in one and it made it to the muffler but I would hope that is not the case. Has anyone else had a flowmaster muffler go bad in 50k or less?

Flowmaster
 

I had a similar situation with a flowmaster years ago.. it was at around 30,000 km's.. one of the chambers broke loose and was rattling up a storm.. once replaced I never had another issue with it and the replacement had about 100,000 km's on it when I sold the vehicle...

Flow****ter's are notorious for their welds breaking loose inside the muffler and doing exactly what you are describing. Id weld up a better muffler if i wereyou, eith Cheery Bomb, Borla, or Magnaflow

I've had several trucks with flowmasters on them and none have had this problem. I heard an f150 with a magnaflow the other day, and I think I may try them out this time around.

You will be better off trashing that crap muffler for a Magnaflow.