MDS "rattle". Is it common?

XXSNOTRODXX · Sep 26, 2015

Hey guys,
2011 1500 sport 4x4 5.7.

My truck runs great,oil is clean and full. Runs whisper quite (not even the typical hemi tick people complain about). BUT, if driving at a low speed...say 25 mph or so when my eco mode pops up on my evic and mds kicks in I can hear a "rattle" in the engine. Not super loud but loud enough I am sure people can hear it as I drive past them.

It doesnt sound like any sort of malfunction or damage. Just sounds like noisy deactivated lifters.

I know it is MDS because I can manually shift the truck or put it into tow haul and the truck stays whisper quite.

My question is, Is it normal to hear this on our trucks?.

smurfs_of_war · Sep 26, 2015

Is it maybe a heat shield or something simpler?
Mine never rattled- it just sounded like it was farting.

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XXSNOTRODXX · Sep 26, 2015

Doesn't sound like a heat shield . Sounds like lifters when 4 cylinders cut out.

smurfs_of_war · Sep 26, 2015

Has it become more pronounced lately?

The 5.7 I had before the 6.4 was always making some kind of tick, rattle, or other noise. BIL is a Ram tech- said sounds like every hemi out there. Mix aluminum, plastic and steele and it turns into a rattle. Perfectly normal. So I never paid much attention to it after that.
The 6.4 noise I have found even more and again- I think they are just noisy mills. I will pay attention when MDS kicks in, see what I can hear.

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XXSNOTRODXX · Sep 26, 2015

Nope, I have had the truck since the end of May and have put about 4,000 miles or so on it and it hasn't got any better or any worse. The dealer I got it from did the oil change on it before I bought it and the truck has not set off an MIL for an oil change yet. Curious if when I do an oil change if it will get any better as i have no idea what kind of oil the dealer used in it. I am assuming they used the correct weight oil but I am sure they used some cheap bulk brand or something.

Sillygoose · Sep 26, 2015

Mine is similar, I guess you could describe it as a rattle. Drives me nuts so I usually just pop it into 5th

R.L.K. · Sep 26, 2015

I'd bet they used the bulk out of a drum , I'd do an oil change now , spend some time on the engine performance thread here and make your own decision on what weight and type to upgrade your oil to .
Several excellent choices out there ie Redline , Purple , Amsoil and Penzoil Ultra Plus and many more synthetic choices , mobil one is a good one , too many to mention .
I believe the bulk oil the dealers use is probably not gonna hurt you engine , but it's not doing much for it because it's about the consistency / viscosity of dirty water !
I'm about to do my first oil Chang on my truck , I've been doing some reading , I'm not sure what brand I'm going with yet but I know I'm certinly not putting the recommended 5-20 in it , I'll likely go with a 5-30wt oil of some synthetic flavor ..

XXSNOTRODXX · Sep 26, 2015

I have always been under the impression that if you run anything other than 5-w20 you run the risk of the MDS not working correctly. My wife has an 05 grand cherokee with the 5.7 and I always use valvoline conventional 5-w20 and it sounds great (Even when MDS engages).

And yes, I know that the debate on oil weight/brand is an endless one haha

MyOhFive · Sep 26, 2015

i know what you're hearing, it's almost like spark knock or detonation. I couldn't tell you what it is, but its the sound the engine makes when you lug it in MDS... and i try to avoid it. Either by giving it a little more or manually dropping a gear to turn MDS off until I'm going faster.

Chip · Dec 22, 2016

I know this is an old post but this is the exact problem I'm having with my 2015 did anybody find out if this is a normal thing?

XXSNOTRODXX · Dec 22, 2016

I think it is just a thing on these trucks. Mine has not got any worse. And I never heard from anyone about a fix. I think from the factory they allow MDS to kick in at to low of a speed which puts to much load on the engine in 4 cylinder mode which causes the noise. They should limit MDS activation to at the least like 45 mph and above in my opinion.

Markcuda · Dec 22, 2016

I will pay attention when MDS kicks in

OK, let me ask a dumb question, how will/do I know when the MDS kicks in?

VB712 · Dec 22, 2016

Mine sounds like a misfire when it kicks in. When I put my exhaust on, MDS makes my truck sound terrible. Eventually I'd like to get a tuner just to turn it off instead of putting the truck in 8th gear everytime I drive it.

DILLIGAF · Dec 22, 2016

Easy solution is to disable that crap

racinjason15 · Dec 22, 2016

If you haven't been to a dealer there is a flash for the pcm. It's pertaining to a vibration like feeling at low speed. I know I flashed mine today. Seems to have changed low speed mds actuation. It's not as noticeable.

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XXSNOTRODXX · Dec 23, 2016

I have not had any flash done at the dealer on mine. However I have no out standing recall/services due. Is it something the dealer notifies owners of? or do you have to personally request it?.

I normally just slap shift to 5th until unless I got above 55 mph. It doesn't harm anything for mds to engage at low speeds I don't believe. It is just annoying .especially with aftermarket exhaust.

RamCares · Dec 30, 2016

XXSNOTRODXX said:
I have not had any flash done at the dealer on mine. However I have no out standing recall/services due. Is it something the dealer notifies owners of? or do you have to personally request it?.

I normally just slap shift to 5th until unless I got above 55 mph. It doesn't harm anything for mds to engage at low speeds I don't believe. It is just annoying .especially with aftermarket exhaust.

Hi XXSNOTRODXX,

There is a TSB that relates to the concern you are experiencing:

"NUMBER: 18-050-14 REV. A
GROUP: Vehicle Performance
DATE: December 09, 2014

SUBJECT:
Flash: Drone or Vibration Present During MDS Operation

SYMPTOM/CONDITION:
New PCM software is being released to address a customer’s concern of a drone or vibration type condition while driving at highway speeds during MDS (Multiple Displacement System) operation."

Your local dealership will be able to identify if this TSB applies to your vehicle and offer further assistance. Please let me know if you have any additional questions!

Andrea
Ram Social Care Specialist

Tony1550 · Feb 15, 2022

I had the same issue about 3 weeks ago and I noticed that my oil pressure was really low , I was getting 28 psi at idle and 35 psi at 70 mph on the highway so I looked into why it was so low and it turned out being the Amsoil oil filter . Turns out Amsoil doesn’t recommend that filter for the ram with the 5.7 hemi and it’s been a known issue for a year . I then changed out the oil with a Mobil 1 filter and the noise went away and the oil pressure went back up. If you’re running Amsoil and you bought the Amsoil oil filter get ahold of them and tell them what’s going , I did that and they sent me 3 quarts of oil for free.

MDS "rattle". Is it common?

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