MDS Growl

[Mike Wenrich]

I know there has been a lot of discussion on the MDS system and whether or not to deactivate upon start up and the consensus may be that if you are not going to idle much then it might be okay to leave on or maybe off. But I have a question for those with this system about the noise it makes when coming off ECO mode. My 2023 has 13K on it. When new I did not hear the growl/groan it makes at all. At about 4,000 miles I started to hear it and now it sounds like I have a modified muffler to make noise like our 60's cars. I drive in the mountains so I'm on and off the go pedal very often due to rolling hills and going into/out of the ECO mode frequently. In stop and go traffic I can hear it growling so going stop light to stop light it's in and out a lot.

Question is...Since I don't do a lot of idling will the engine get the oil it needs for the lifters if I deactivate for the mountain driving and is it normal for the noise it makes to increase as the miles pile up. Don't like the hesitation going out of the mode either but it's only a second or so. If I do open highway driving with no hills it's really not an issue but annoying to drive in the hills. Appreciate your thoughts on this. I don't want to hash an issue that has been discussed a lot but I do want to make sure the increased noise is "normal".

 

[joesstripclub]

From what I recall, MDS only kicks in over 25 mph and under 80 mph, so you shouldn't hear it at all during idle. Wondering if you are hearing a different noise?

 

[Mojo88]

I deactivated my MDS in the tune, I hated the noise and the feel. It sounds to me like you are describing the noise as MDS activates, i.e., it sounds like an old farm tractor or something. When MDS de-activates back to 8-cyl mode, the engine should run perfectly smooth again.

 

[Mike Wenrich]

It runs smooth and the growl is definitely the MDS. Just looking for input on what others with the 6.4 and 8 spd trans are hearing and if the getting louder as it adds miles is an issue. An annoying issue at that but I don't want to diminish the valve train of oil by disabling it. Seems if I am driving and not in stop and go traffic it might be okay to disable it. I do get tired of hearing/feeling it. But not bad enough to go into the engine and convert the system. The pre MDS 5.7's seem to do well w/o it and not so well after it was built in. Maybe I would be better off turning it off but seems I have read on this forum that changes the amount of oil getting to the cam and lifters.

 

[Mojo88]

.....The pre MDS 5.7's seem to do well w/o it and not so well after it was built in. Maybe I would be better off turning it off but seems I have read on this forum that changes the amount of oil getting to the cam and lifters.

Yes, I read as many of those posts as I could before I turned my MDS off. Seems like a lot of idle time contributes to the issue, so I don't let it idle. Additionally, many of the YouTube videos on the topic reference possible splash oil scarcity onto the cam/lifters at idle as the specific issue, so I am (based on advice from this forum) using 7 qts oil plus 1/2 qt Lubegard, thus slightly overfull, creating more splash oil up into cam/lifter area, that's the theory anyway.

 

[Tulecreeper]

I know there has been a lot of discussion on the MDS system and whether or not to deactivate upon start up and the consensus may be that if you are not going to idle much then it might be okay to leave on or maybe off. But I have a question for those with this system about the noise it makes when coming off ECO mode. My 2023 has 13K on it. When new I did not hear the growl/groan it makes at all. At about 4,000 miles I started to hear it and now it sounds like I have a modified muffler to make noise like our 60's cars. I drive in the mountains so I'm on and off the go pedal very often due to rolling hills and going into/out of the ECO mode frequently. In stop and go traffic I can hear it growling so going stop light to stop light it's in and out a lot.

Question is...Since I don't do a lot of idling will the engine get the oil it needs for the lifters if I deactivate for the mountain driving and is it normal for the noise it makes to increase as the miles pile up. Don't like the hesitation going out of the mode either but it's only a second or so. If I do open highway driving with no hills it's really not an issue but annoying to drive in the hills. Appreciate your thoughts on this. I don't want to hash an issue that has been discussed a lot but I do want to make sure the increased noise is "normal".

I have 12k on mine and the only thing I notice is when I let the MDS do its thing I can feel a rumble/growl through the gas pedal when it goes into 4-cyl mode, but I don't actually 'hear' anything. I bugs the heck out of me, so I generally just override it with my ERS and keep it in 8-cyl mode all the time.

 

[Wild one]

It runs smooth and the growl is definitely the MDS. Just looking for input on what others with the 6.4 and 8 spd trans are hearing and if the getting louder as it adds miles is an issue. An annoying issue at that but I don't want to diminish the valve train of oil by disabling it. Seems if I am driving and not in stop and go traffic it might be okay to disable it. I do get tired of hearing/feeling it. But not bad enough to go into the engine and convert the system. The pre MDS 5.7's seem to do well w/o it and not so well after it was built in. Maybe I would be better off turning it off but seems I have read on this forum that changes the amount of oil getting to the cam and lifters.

Mufflers do "break-in" and get louder with time. Use the ERS buttons to keep it at or above 2,000 rpm,and you'll be okay then as it'll get enough cranksplash to keep the cam lobes lubed,and as stated don't let it idle anymore then you have to.Don't be scared to use the skinny pedal,as the hemi's an engine that doesn't mind being drove a bit aggressive,driving one like Grandma doesn't do them any favours

 

[Randy Grant]

Do you have e-torque?

 

[DanAR]

Maybe it’s some hearing loss but if I didn’t look for the ECO light coming on I wouldn’t know my 23 truck has it. It’s completely transparent to me so far - no noise or vibration - nothing. But I’m pretty low on miles so maybe it’s something that comes on with more miles.

 

[Papa Red]

I'm with Dan above. I don't hear or feel it. I only know it's on by seeing the dash light. I have 35,000 miles on the truck.

Red

 

[Musky Mike]

Sounds like a problem with Active Noise Cancellation (ANC). I have a problem with mine that took me a while to figure, it only happens to me when MDS is on, during decelerations with my rubber a rubber made tote in the back seat. They make a cable to bypass the ANC, it plugs into the amp under the drivers seat. Take a few minutes to install.

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[Mojo88]

Sounds like a problem with Active Noise Cancellation (ANC). I have a problem with mine that took me a while to figure, it only happens to me when MDS is on, during decelerations with my rubber a rubber made tote in the back seat. They make a cable to bypass the ANC, it plugs into the amp under the drivers seat. Take a few minutes to install.

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Good post, and a clever suggestion. I installed one of those bypass cables (from that vendor) a few months ago, because I have the HK system and am planning to eventually install a better subwoofer and separate amp, so the bypass cable is a necessity for that.

Even with the ANC bypassed, I have noticed ZERO difference in the interior noise levels. However, I can certainly see how an ANC problem could cause a puzzling noise issue.

 

[Mike Wenrich]

Answering the question re: do I have e-torque, not to my knowledge. I believe that is only on the 5.7. Mine is heavy duty Laramie 2500 6.4. Interesting video on the ANC. I'll check today if there is a difference with window down or up. I don't believe that's it because I can feel the vibration on the pedal but maybe my brain is telling me that. I'll also try this with the radio volume off, or at least turned down. Don't know if I can turn it off.

ANC...Another Nincompoop Conception. ARRRRGH.

 

[Mojo88]

..................ANC...Another Nincompoop Conception. ARRRRGH.

Yeah, a lot of this tech seems pointless. However, I actually like most of it. For instance, a few nights ago, I was trying to plug a USB stick into one of the ports just in front of the center console. It was kinda dark in my garage, so I was gonna go grab a flashlight, but as I was poking the USB stick around (I knew I had it close), the stick was detected just by getting it close, and some small LED lights around the USB ports activated, and I could clearly see where to insert the stick. I was rather impressed....

 

[mikeru]

Maybe it’s some hearing loss but if I didn’t look for the ECO light coming on I wouldn’t know my 23 truck has it. It’s completely transparent to me so far - no noise or vibration - nothing. But I’m pretty low on miles so maybe it’s something that comes on with more miles.

I'm with Dan above. I don't hear or feel it. I only know it's on by seeing the dash light. I have 35,000 miles on the truck.

Red

Having owned several 1500's with MDS I can say it varies greatly from truck to truck. My first truck with MDS was a 2017 Rebel. MDS was very noticeable on that truck and I quickly got used to disabling it. The wife's first truck with MDS was a 2016 Laramie. And on that truck neither of us could tell when it was on or off. Even on 5th gens there can be differences. On our current 2020 Limited I can hear it but not feel it. On our previous 2021 Limited I couldn't tell.

I haven't owned an HD so I have no experience with the 6.4 Hemi, but I suspect it's going to play out the same. It will be more noticeable on some trucks than on others.

 

[Musky Mike]

Answering the question re: do I have e-torque, not to my knowledge. I believe that is only on the 5.7. Mine is heavy duty Laramie 2500 6.4. Interesting video on the ANC. I'll check today if there is a difference with window down or up. I don't believe that's it because I can feel the vibration on the pedal but maybe my brain is telling me that. I'll also try this with the radio volume off, or at least turned down. Don't know if I can turn it off.

ANC...Another Nincompoop Conception. ARRRRGH.

I'm not an expert on ANC, I think it is suppose deactivate with the window open, but on my 2019 the window down didn't stop the grown/howl/growl/drone. The only thing that stopped it was turn off MDS, take rubber tote out the back seat or by pass the amp. I also don't think turning off the radio turns off ANC.

 

[dieselscout80]

Answering the question re: do I have e-torque, not to my knowledge. I believe that is only on the 5.7. Mine is heavy duty Laramie 2500 6.4. Interesting video on the ANC. I'll check today if there is a difference with window down or up. I don't believe that's it because I can feel the vibration on the pedal but maybe my brain is telling me that. I'll also try this with the radio volume off, or at least turned down. Don't know if I can turn it off.

ANC...Another Nincompoop Conception. ARRRRGH.

I had a noise from my 2020 Ram 2500 6.4 that I thought was the MDS. However, it was the exhaust pipe tie bar / brace between the two pipes just to the the rear of the cats. Once I welded it the noise has NOT returned.

 

[weldguy]

Do Rams have Active Motor Mounts to hide the vibrations during MDS? Some manufacturers use motor mounts that electronically produce vibrations to cancel the MDS vibrations. One of these mounts can be perfect mechanically, but allow MDS vibrations.

 

[bjayscanlon]

I have a 2023 and never hear anything related to the MDS. I see the ECO light and know is is not necessarily related to the MDS. So, I wonder, is it on, or is it not. It is completely stock and runs great. Now have 15K miles racked up.

 

[Wild one]

Do Rams have Active Motor Mounts to hide the vibrations during MDS? Some manufacturers use motor mounts that electronically produce vibrations to cancel the MDS vibrations. One of these mounts can be perfect mechanically, but allow MDS vibrations.

They use a vicous/oil filled motor mount to dampen engine vibrations