I kinda figured...4x2 trucks have a aluminum d/s.
What your hearing w/that exhaust is the MDS drone. when your truck goes to 4cylinder mode it sounds like a helicopter flying underwater. These trucks came from the factory w/ a 30" muffler and at least on resonator on the tail pipe to suppress the drone. Obviously yours has been modded. I put in an 18" Mag and left one resonator in before the muffler, the drone is still there just not too bad.
You could eliminate the tail on the drivers side w/ a single in single out Magnaflow and that will quiet it down as well.
Just don't get talked into a flowmaster...they're chambered and kinda what you got on there now.

 

Buy a Saturn if you want quiet.

 

It is loud all the time but we also hear what you call "sounds like a helicopter flying underwater" (great description). Actually I never had a clue that it ever went into a 4 cylinder mode.....news to me. My gawd, how bad would my mileage be if it didn't do that? I just looked at the Magnaflows at Autozone and the prices are not that bad. Just not sure how I could mig the new muffler in there. Guess that I will have to break down and price something at a bona fide muffler shop. Thanks for all the info.

 

Your mileage will actually be better if you turn the MDS off. Dodge MDS is known for kicking in and out of MDS so much that it actually wastes more fuel than if it was just using all 8 cylinders all the time like God intended it to. Plus can you imagine how much extra it would take to move your truck with only 4 cylinders? Yea neither can I

 

It all depends how and where
you drive. Flat areas, highways
and interstates MDS saves gas.
If you drive it like a raped ape
not so much...they wouldn't keep putting it in 1500s if it didn't work.

 

When does mds switch on? I've heard it's when you aren't giving it gas but it sometimes feels underpowered when I give it gas. That may be because I need to regear it. Is it difficult to turn mds off?

 

Although you did not add anything meaningful to the thread I will still answer your question. They don't make Saturns anymore and besides my Lexus is quieter than any Saturn that was ever made.

 

I thought God only made one Saturn? I learn something new every day on this forum!

 

MDS is as easy to turn off at a push of a button... On a tuner. Does MDS work on flat roads? Yea but as soon as you hit a head wind it will kick off and you'll be back in 8 cylinders. I don't drive like a "raped ape" and I hated it, at first I thought it was the bees knees but now that it's gone I don't miss it one bit. And RAM still uses it so they can tell the government that they're making an effort to save fuel and the world. MDS is crap in my opinion

 

Yeah....like they said kill the MDS. Get a big Maganflow, Dynomax SuperTurbo or a Cherry Bomb Elite to get less sound.

Or you could do what I did, a stock muffler off a 09+ Ram with the factory dual outlet muffler. I picked mine up on Ebay for very little.

I did this when I was towing my boat 7 hours one way two times a summer fishing in "up North" MN. Now I wish my truck was louder again, sold the boat. I might be redoing my exhaust soon with a Cherry Bomb Elite. Good luck.