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Discussion Starter #1
I have had my car for about 6 months now and the other day I started to notice a noticeable humm when I am cruising at around 50 miles per hour. It almost sounds like the car wants to change gear, but the RPMs are still between 1-2.

I have not heard this prior in my car and started to notice it. I am not sure if it has to do with the ECO, but it sounds a tad out of the ordinary. I am also not sure if it is the tire, but those are pretty darn new.

Any ideas on what this could be? I mean I know it is a hemi, but it just sounds off to me.
 

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Discussion Starter #3 (Edited)
Starts at around 50 mph when you first hear it. RPM is around 2.

If you are just crusing at 50-60 at a constant speed you notice it.

I haven't had a chance to get on the highway lately to get to higher speeds.
 

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Discussion Starter #5
It does kick in. However, my buddy has a 2012 Charger RT and it sounds nothing like what I am hearing at the same speeds. Figure that is as close as a comparison as I can get.
 

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It is 100% the MDS kicking in and moving back to 8 cylinders when you start to slightly hit the gas. It really annoyed me when I first got my car. I would be either cruising on the express way or cruising in town. When I keep my foot on the gas and just slightly press it to either slowly speed up or just keep the pace, I would hear a bit of drone and feel it in the pedal. I thought it was having problems changing gears and it also felt like something somewhere was loose. Dealer couldn't figure it out...turns out I figured it out. It is the MDS system and when I got my Diablo Tuner, I disabled the MDS and the problem is completely gone and it is a HUGE wait off my worrying mind. it is so smooth now and much more responsive...not because of my tune, but because I turned MDS off and tested it without tuning the car at first. Turns out that some of the cars and drivers just experience the MDS feel/sound more than others. it is actually operating properly, but damn annoying.

get a tuner and turn it off. I dont experience a huge difference in mileage, plus you can enable it again before long trips to get better mileage.

Hope this helps.
 

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Also, the ECO light is not directly related to the MDS. It is a good estimate of when the MDS is kicking in and out, but even with the MDS disabled, the ECO light will still work based on how you work the gas pedal...pretty good feature for watching your mileage.
 

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Yes, the main reason I got the DS tuner was to turn off the MDS. It was real annoying between 35-50 and the operation was not smooth. My wife just bought a new 2014 Ram Laramie 1500 with the Hemi and MDS. You cannot tell when it kicks in and out. It also has the 8 speed auto and so far I am really impressed with the Hemi / 8 speed combo.
 
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