When I get to 2800rpm my exhaust will make a howling sound until about3000 rpm or so and will do the same thing on the way back down the rpms regardless of any conditions. The best way I could descibe the sound it makes is as if you were blowing across the top of an emptybeerbottle. I just replaced the muffller with another OEM muffler because the old one was rotted out, andI also verified there was no other holes or leaks in the exhaust system and thisdid not help. At most it is a little annoying, but I was wondering if anyone else has this sameissue and what causes it. Do any of you with exhaust mods experience this? Sorry if this is a repost, I have done a search with no luck. Thanks in advance for any feedback.

'02 QC Sport,4x4, 4.7L, 57K miles- STOCK

 

Sounds like you got an exhaust leak somewhere. That's the sounds you get when theres a leak in it somewhere. Not like anything is that wrong but You will have to look around and try to find it. But don't be too worried about it. Once the leak is fixed ur good to go.

 

Exhaust leak

 

Perhaps a collapsed pipe?

 

I had a chance to get out and look over the exhaust system again and there definately isn't any collapsed pipes. The only hole I could find is the drain hole at the rear bottom of the muffler (see pic), would this little hole cause the howling noise between 2800 - 3000 RPM?. Also, I have attached a pic of the exhaust system ahead of the muffler.Is there supposed to be anything where the straight pipe is ahead of the muffler??? As a side note, as you can see in the picture I have a steel drive shaft, I have noticed in other posts that some of you have an aluminum drive shaft. Is the aluminum drive shaft an option or does it comewitha certain package?

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