Hum when hemi drops to 4cyl

cajun87 · Jul 19, 2013

I have two rams, i have a 2012 with the 4.7 v8 and a six speed auto and a 2013 with the hemi and the auto8. When the 2012 drops to 4 cylinders its seamless and unnoticeable. My 13 has a slight hum almost like a exhaust noise when it drops down to 4 cyl. At 60 mph my 2013 is doing 1500 rpms and is in 4 cyl mode. I can hear the hum and feel a very fait vibration. Sometimes it irritates me and i just hit the minus button on the wheel to switch back to v8 mode. Is this normal for this engine trans combo or is something out of balance. My 2012 doesn't do any of this.

IHRedRules · Jul 19, 2013

I don't think the 4.7's came with the MDS (4 cylinder) system.

Jabalone · Jul 19, 2013

cajun87 said:
i just hit the minus button on the wheel to switch back to v8 mode.

Cool. I didn't know that.

cajun87 said:
Is this normal for this engine trans combo or is something out of balance.

I don't hear that on my 2013 at all so don't think it's normal. I have the 6 spd hemi.

joeg45 · Jul 19, 2013

If you have an after market (louder exhaust) you will deffinatly notice on a stock exhuast you would probably have to be really really listening to it to even notice it but I don't know about the a8 that's just my experience with the "6" & "5" speed trans

And I don't think the 4.7 can do that

Chewy · Jul 19, 2013

It was almost unnoticeable with my stock exhaust and is only slightly more noticeable with the 24" Magnaflow.

I have the A8!

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Stangshcky12 · Jul 19, 2013

There's a slight whiring noise when my dads '11 switches

VolsRam · Jul 19, 2013

I never noticed it before I removed my muffler, but since I removed it is very noticeable. I have the '13 Hemi with the 6 speed. It sounds a lot like a big rig winding down in 4th gear at a high speed. I don't mind it. I like loud exhausts, so it makes it seem louder.

cajun87 · Jul 20, 2013

Yes my 4.7 definitely drops down. It has the eco mode in the evic screen and everything.

I have the stock exhaust for now, goin' be a loud som ***** one day

mattman_13 · Jul 20, 2013

The eco symbol can mean you are driving economically on the 4.7s. I def noticed when my 2012 was stock when it would be kicking into 4 cylinder mode so I would suspect yours is normal too. Some people pay different levels of attention to certain things so some notice and some don't.
Here is a good read on the 4.7 if anyone is interested. I read it just to try to confirm my assumption the 4.7 doesn't have MDS but can't confirm nor deny from this article
Next generation V8 engine - the Dodge/Jeep 4.7 liter V-8

apepe0738 · Jul 20, 2013

The MDS is only on the Hemi. While both have the eco light, it is only there to tell you that you are driving "economically". Even in the Hemi, the eco light does not mean you are in MDS mode. Probably why you don't hear or feel any differences in the 4.7 like you do in the Hemi.

Stangshcky12 · Jul 20, 2013

As far as I know only 300C, Chargers, Challengers, Grand Cherokee, Commanders, Aspen, Durango, Magnums and Ram 1500 with 5.7 Hemi have

BlownGP · Jul 20, 2013

I notice it by sound as much as I do driving it and I have a flowmaster.

Now hitting the tow/haul button makes a noticeable difference in the way it drives/sounds especially slowing down to a stop. Sounds like I have jake brake..haha

FrenicX · Jul 20, 2013

I have heard some describe the sound as like a helicopter when it drops to 4, with an aftermarket exhaust.

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garner · Jul 20, 2013

cajun87 said:
Yes my 4.7 definitely drops down. It has the eco mode in the evic screen and everything.

I have the stock exhaust for now, goin' be a loud som ***** one day

Only hemi have mds

loveracing1988 · Jul 20, 2013

I can definitely tell when mine switches to 4 cylinder mode, but I find little issues with vehicles that no one else does so I don't know how much the average person is going to be able to tell. I drove mine for a good drive on the expressway today and was so happy the thing was staying in 4 cylinder mode except when going up hills, I figured the higher octane and breaking in were ready helping, then I realized I had about a 10 to 15 mph tailwind, but I could tell the whole way when the mds kicked in and out.

cajun87 · Jul 20, 2013

Well now i know that the 4.7 is a **** all by its self. I was thinking it was a **** because of the mds.

Hum when hemi drops to 4cyl

cajun87

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IHRedRules

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Jabalone

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joeg45

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Chewy

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Stangshcky12

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VolsRam

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cajun87

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mattman_13

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apepe0738

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Stangshcky12

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BlownGP

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FrenicX

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garner

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loveracing1988

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