Originally Posted by Chromeshadow

I think there are 3 or 4 on the single exhaust, one at the tip, one on the front and the rear of the muffler.
Since there is no flex coupler in our exhaust, the engine vibration and movement is sent directly to the entire exhaust system. Every time you hit the gas, the engine rocks a little and this goes through the entire exhaust system. These rubber mounts get a lot of abuse. They look a little like a figure 8, there is a tool to remove them or you can lube them up with dish soap and pry them off and on. Oil (WD-40) eats them up (IMHO) and should not be used.

Originally Posted by Chromeshadow

It could be true. But if the rubber exhaust hangers are broken, I'd start with them. There are a couple of heat shields that can rust and loosen up that may rattle.
I put 200,000 miles on my 2000 3.8 and the cats were fine. I usually drive at least 30 minutes, no short city hops, means my cars get warmed up enough to get all the moisture out of the exhaust. I would think if the cat were rattling, you might throw a code. Do you drive a lot of short distances?

Originally Posted by LordRipberger

Hey Guys,

My car started making a noise yesterday that has me concerned. I will take it to the ford dealer today if they have space, but I wanted to see what you guys thought in the hopes of having some idea of what to expect when I go.

2006 v6 Mustang - everything original, no mods - 117k miles

Once I get to 1500rpms it sounds like something is rattling back and forth, almost like it is rattling around inside a metal box. By the time I get to 2000rpms the sound disappears (or the car is too loud to hear it). It appears the noise is coming from underneath the car, around the area where we sit in the car. I can cause the sound at the same rpms while in neutral, so that leads me to believe its not the transmission, but rather something has come loose and the 1500-2000 rpm range is its happy place to make sounds loud enough for me to hear.

My acceleration doesn't seem to be effected, the car doesn't shift hard, nothing seems out of the ordinary except the sound.

Thank you for your input.

Originally Posted by LordRipberger

The dealer said my right cat broke and that is what is causing the rattling. They put it on a lift and starting hitting the cat and pipe with a rubber mallet to show me the rattling noise. Although this makes sense, would driving really cause the same noise? Hitting it with a mallet is not the same as driving down the road causing a vibration.

thanks.

Originally Posted by Drastang

is this a automatic or a manual ? I don't know that much about your years but I have a rattle every gear at 1500-2000 and thought it was my clutch// tranny had it for 4 years found out this week while disassembling car my trans mount was broke.

Originally Posted by Derf00

What do they mean broke? A weld point on the body is broken, the shield is bent or has a broken weld spot, the internals catalytic mesh broke free of the body....?

Harmonics are a funny thing. Yes, you can replicate a sound coming from a suspect component in some cases by hitting the correct part with a rubber mallet. The mallet causes the surfaces to resonate like they would while you're driving down the road. When the Engine is spinning at 1500 RPM and driving down the road, the conditions are at just the right harmonic level and/or frequency to cause vibration of the part that is causing you the noise, it's called the resonating frequency.

It's how a tuning fork for a piano works.