I've been running the 41" Donaldson on my truck for the last 7 years and either my ears aren't what they used to be or the truck has gotten louder. There is a constant deep hum in the truck that becomes very fatiguing, very quickly when you are over 1800 RPM. I recently test drove a 2014 and I realized how loud my truck really is.

My question is, for those of you who still run the stock exhaust, is your truck tolerable on the highway for extended periods of time? Can you hear your exhaust like I can? It's been so long since I've been stock, I forget.

I realize I can go with the 51" Donaldson for less than factory, but I want as quiet as possible. The truck has no modifications.

Thank you.

 

My 05 has stock exhaust and its the quietest cummins I have ever been in. The most noise I hear is wind noise coming through the door rubbers. My 94 has a straight 4" and I have to wear earplugs at highway speeds.

 

Assuming your truck still has the catalytic converter installed it should be very quiet with the 41" Donaldson.

I guess it's possible that the Donaldson muffler has gotten sooted up and is now louder over the years.
Perhaps you are due for a replacement Donaldson?

Another option would be to add another small straight thru muffler/resonator to further quiet things down a bit.

Another option is to add a 2nd turbo. It will definitely quiet things down a bit and has further benefits also!

 

I'm running the stock exhaust and no plans on changing until it literally falls off the truck. The engine/turbo is louder than the stock exhaust.

Best bet is to jump up to the 51" Nelson or Donaldson muffler.

 

Stock exhaust seems fine and I love be able to occasional whine of the turbo.

 

150k miles on my stock exhaust and in my view, the noise is just a low hum, no bother at all.

 

The stock exhaust on the 2004.5-07 trucks is 4.0" OD and mandrel bent. It's quite free flowing including the cat except for the stock muffler.

The stock muffler is quiet but it's like a black hole. What goes in doesn't come out!
It was one of the 1st things I tossed when I got my truck new back in 2004.

http://www.dieselpowerproducts.com/c...mponentsb.aspx

 

I have the 51" donaldson and it is not as quiet as the stock muff, there is no drone hauling my 36ft 5th wheel, I have a S&B intake and I hear the turbo whistle, I still have the cat, the only good thing is my EGT`s are a little bit lower, nice sound though,

 

On the highway, my truck is quieter than my mom's subaru. As said above, I'll leave the stock exhaust in place until it falls apart. In CO, that's a long time.

 

Thanks everyone. I'm probably going to spend 60K to fix my loud truck, by upgrading to a 2014. They sure ride nice and have many creature comforts. Hopefully they've upgraded some of the 3rd gen front end issues.