Low frequency noise from rear end at highway speed?

[GeoJoe]

I have a 2019 Ram 5.7L, with 3.92 rear end. I've noticed a rather loud base like drone coming from the rear end during highway cruising at 0-15% throttle. Can anyone enlighten me on what the source might be? My truck is new less than 900 mi on the clock, so I don't believe it's wheel balance.

 

[Richard320]

Is it constant, or does it cycle?

I had a regular consistent cyclic drone on level ground with cruise on at 72. Every twenty seconds or so. It was the noise cancelling. A reflash fixed it. There is a TSB, but it took some nastiness on my part to get them to perform it.

 

[RamCares]

I have a 2019 Ram 5.7L, with 3.92 rear end. I've noticed a rather loud base like drone coming from the rear end during highway cruising at 0-15% throttle. Can anyone enlighten me on what the source might be? My truck is new less than 900 mi on the clock, so I don't believe it's wheel balance.

Hi @GeoJoe - If you are not able to determine a solution based on suggestions from fellow forum members, and you decide to address this with your dealer, we are more than happy to get you connected with a specialist who can provide an additional layer of support through that process. Our team is always a private message away.

Mark
RamCares

 

[GeoJoe]

Is it constant, or does it cycle?

I had a regular consistent cyclic drone on level ground with cruise on at 72. Every twenty seconds or so. It was the noise cancelling. A reflash fixed it. There is a TSB, but it took some nastiness on my part to get them to perform it.

It seems to only happen when the truck goes into eco mode, cylinder deactivation? Is this normal?

 

[Richard320]

It seems to only happen when the truck goes into eco mode, cylinder deactivation? Is this normal?

Yes and no. Common, but not supposed to be. It's either the noise canceling not working, or those counter-vibration things mounted on the frame. Take it to the dealer and ask them to check for TSBs.

 

[FastBlackRam]

It's not normal. Some will disagree, but if you manually shift down when in ECO mode, the ECO light will go out, as it seems to simultaneously exit the 4 cylinder mode. At that point the droning should cease. Indicating it is the noise cancelling frame devices that may be not phased correctly. Good luck getting the dealer to fix it.

FYI, I got 2 tires replaced when I noticed a high speed vibration, as they couldn't RF balance them and had to replace them. That problem is GONE. My unbalanced tires did not present as the sound you are describing.