Exhaust Rattle and blowing + Maintenance course

[Dead Eye]

HJFazer - Do as Jamieg285 has posted in regards to remove the can. The gasket is a sort of wire mesh if I remember correctly and it should be obvious. It will most likely be stuck on the inside of the pipe on the can end. This is all a bit of assumption and based on what you said in your original post but it won't hurt to check it out - if its a really loose fit this will probably explain the grinding you noticed.

To clarify, can you describe exactly where the exhaust is blowing from? Photos if available would be ideal