I have a really bad noise coming from my left hand exhaust (the left hand side as if facing the rear) it sounds like a throaty rattle which sounds worse on excellaration, it sounds quite tinny. I've been told i need a new back box (could this be the baffle?) if so I imagine i will need a new back box whatever this is (I am not mechanically minded). If this is the case i have had a quote from nissan for £430 for the part only, is there a cheaper way of doing this or anything else I can do. Is there another part i can buy to fix the problem. I have also been told I can get a new back box for about £40 from online stores does this mean I would need two back boxes so that both exhausts are the same. I appologise if this sounds like a stupid question but I really have no idea what a back box is or what it is I need to do to sort the problem out.

 

The English and American terminologies differ, so I'm not sure I understood your problem 100%. So I apologize in advance if what I'm posting is completely irrelevant.

It sounds like you might have a leak. If you have a leak, you first have to find it. Take it to a welder (with the troublesome piece) or an exhaust shop and get the leak fixed. If it's the internals of the muffler, resonator, or the flex pipe, you'd probably have to replace it. If that's the case, it's better to get an aftermarket exhaust rather than buying the factory one.