dediesel

Brand New auto quad cab. Exhaust is very loud around 2000 RPM under a mild or greater load. Seems to come from the muffler. This seems to happen at about any speed under these rpm and load conditions so I hope that it is not the 70MPH vibration that I have read about. It can be heard while accelerating in any gear above 1. I have driven other similar Cummins and have not noticed it.

Your ideas are appreciated!

Lrdchaos

Maybe one of the mounts is loose and causing some type of harmonic noise, don't know. But go drive another new truck and if it doesn't do it take yours in and have it fixed, especially since it is new.

dediesel

I have a dealer appointment but as I am sure others have experienced, it minimizes the return trips to the dealer if you can point out the problem to them. The laud exhaust has a very deep tone.

staarma

It is a harmonic issue that all of these trucks have. Mine is almost gone iwth a 5" turbo back. It also revs a lot freer through the same RPM than it did stock.

dediesel

With more driving today, I learned that the deep loud rumble happens from 1500 to 2200 rpms. It is almost always noticeable above 30 mph. When the engine shifts, the pitch of the rumble also shifts with the RPMs.

Even when you raise the engine RPMs in neutral there is an unusual rumble noise, although not near as bad as under a load. I am thinking that it might me an engine vibration or exhaust drone.

I don't want to get into aftermarket exhaust etc and give the dealer or Dodge a reason not to take responsibility. I took a ride with the Service manager and he guessed at several things including driveline angles which did not make much sense to me because the rumble changes with the pitch of the engine.

I really like the truck and I want them to fix it but I am getting a sinking feeling. I could sure use some encouraging ideas.



Thanks!

skyfi

Check the muffler bearing.


Sorry I couldn't help myself.

v8440

Driveline angles? Is there another dealer near you that might have a service manager with a clue? Just wondering, that's all. No, you don't have the 70 mph vibration. That actually has to do with the drivetrain, specifically the front driveshaft on 4wd models. If the service manager thinks the drivetrain might cause a drone that varies with engine speed, I foresee a bright future for him in the fast food industry. Sorry, just feeling a little mean today!

rockittboy

sounds like the drone all these trucks have at 2k-2.2k rpms. its just harmonics and exhasut noise out of the motor. actually, some exhausts HELP it go away and some make it worse. then again, you may be describing something else in which case ill just shut up

PourinDiesel

If you want a sure way to reduce noise get a resonator installed.
I did this to my 5" exhaust system and it cut down the drone by about 40%.

rockittboy

good things have been said about aeroturbine.

Syndicate

I hear the Honda truck has a quiet exhaust.

I bet after a ride in my truck you wouldn't bother the dealer any more about it. LOL

Rambunctious1

Never knew that a stock exhaust could produce the drone. I thought it was only aftermarket.

rockittboy

ditto what syndicate said...my dad complained about his 4" flopro system being loud til he heard me drive by with the 5" str8 pipe dumping out under the cab...since then he loves his

WSA308

I have a 4" flopro (cat removed) and have a serious vibration in the exhaust system. Could here an intermitant vibration at the back of thw cab. I thought one of my hangers was loose (no such luck, it would have been an easy fix). All the hangers were installed in the stock position.

In attempt to isolate where the vibration was comming from, I held a screwdriver to the exterior of the exhaust pipe starting from the turbo to the tail pipe. The most significant vibration was located on the straight pipe portion just infront of the inlet side of the muffler. Maybe since the aftermarket muffler is significantly lighter, it has less vibration dampening? Or maybe the configuration of the muffler is creating a shock wave, thus causing the drone/vibration?

I will be follwing this up with a series of calls to various muffler shops and will post any information I gather.

Rod_Montana

One of our two leased trucks (2500 SB) had this problem. Turned out to be contact between exhaust system and truck frame, which transmitted itself as a loud hum at some but not all engine speeds. Simple dealer fix.