Booming/Vibration/Drone at Low RPM - '17 Ram 1500 Hemi

[trmck]

I have a 2017 Ram 1500 5.7 CC 4X4 with the 8HP70 and 3:21 gears. Have owned since new and only have about 15,000 miles on it. Since day one the truck has had a brutal "booming" or drone at low (~1200-1500) RPM. Worst is around 34MPH in town with light throttle. Only happens when (I assume) the MDS is active. "Manually" selecting gears on the wheel gets rid of the issue right away. It's really loud sometimes; like there is a subwoofer in the cab. It's pretty consistent but get the "could not replicate" response whenever I take it in. Have had passengers comment on it as well. I've driven other Ram's similarly equipped and haven't had the same issue (understanding that some level of noise/vibration from the MDS system is common). This seems excessive in comparison. The truck is factory stock with the exception of a tonneau cover and an RA4 radio upgrade (no difference before or after either item).


I haven't found anything conclusive to date; seen a few different threads talking about a flash that helped the issue (on 16 and older models though), I've heard some talk about exhaust resonance, some suggest the TC may be a the culprit, others mention incorrect factory fill of the trans. I've also heard people having issues with the ANC systems but this seems to only apply to 5th gen models. I'm going to take the truck to a local trans shop I trust and get them to do some diag. The guy does a lot of builds for tractor pull trucks and seems to have his stuff together. Hoping for an unbiased 2nd opinion.

I'm almost at the end of my 3 years for the "bumper to bumper" warranty so hoping to get some resolution before that becomes a factor. Ramcare isn't an option (Canada) and I'm getting nowhere with the 1-800 number I was provided. I live in a rural area so dealer options are limited. Hoping someone can point me in the direction of a TSB or something that I can reference during my next appointment. I'm going to start pushing this pretty hard with my dealer but would appreciate any suggestions on something solid I can dig into on this. Thanks!

 

[rowemesp]

I have a '17 Crew Cab 5.7L and know exactly what you're saying. I think that when MDS kicks in at low RPMs that's just gonna be what it sounds like. Personally, I don't think it's bothersome--I don't spend much time in that power realm anyway.

 

[duckman631]

I have a 2017 Ram 1500 5.7 CC 4X4 with the 8HP70 and 3:21 gears. Have owned since new and only have about 15,000 miles on it. Since day one the truck has had a brutal "booming" or drone at low (~1200-1500) RPM. Worst is around 34MPH in town with light throttle. Only happens when (I assume) the MDS is active. "Manually" selecting gears on the wheel gets rid of the issue right away. It's really loud sometimes; like there is a subwoofer in the cab. It's pretty consistent but get the "could not replicate" response whenever I take it in. Have had passengers comment on it as well. I've driven other Ram's similarly equipped and haven't had the same issue (understanding that some level of noise/vibration from the MDS system is common). This seems excessive in comparison. The truck is factory stock with the exception of a tonneau cover and an RA4 radio upgrade (no difference before or after either item).


I haven't found anything conclusive to date; seen a few different threads talking about a flash that helped the issue (on 16 and older models though), I've heard some talk about exhaust resonance, some suggest the TC may be a the culprit, others mention incorrect factory fill of the trans. I've also heard people having issues with the ANC systems but this seems to only apply to 5th gen models. I'm going to take the truck to a local trans shop I trust and get them to do some diag. The guy does a lot of builds for tractor pull trucks and seems to have his stuff together. Hoping for an unbiased 2nd opinion.

I'm almost at the end of my 3 years for the "bumper to bumper" warranty so hoping to get some resolution before that becomes a factor. Ramcare isn't an option (Canada) and I'm getting nowhere with the 1-800 number I was provided. I live in a rural area so dealer options are limited. Hoping someone can point me in the direction of a TSB or something that I can reference during my next appointment. I'm going to start pushing this pretty hard with my dealer but would appreciate any suggestions on something solid I can dig into on this. Thanks!

Turn off mds every time you get in and put it in drive till it becomes second nature. On steering wheel hit Gear down the gear up till 8. You want 8 cyl running at all times.

 

[Dave2018]

You don't have an aftermarket exhaust do you? Just wondering. Could it be an exhaust part touching the body and resonating?

 

[trmck]

Just thought I’d update in case anyone else was having the same “issue”. I’ve concluded this isn’t anything mechanical to worry about. I was originally worried it was something in the TC (I used to have a Ford with an AODE trans that was notorious for TC lockup issues). In my case, I’m pretty confident this is just a resonance in the exhaust. I’m not a physics major but I’ve been reading some stuff about resonance and it seems to line up. I’d notice it more when it was cool out and I think the combination of the rubber hangars being “harder” at cooler temps and (what I understand to be) the behaviour of sound waves at a lower temperature seem to add up.

I was bored during our COVID lock down and installed a Lyell’s Performance Exhaust stainless muffler (excellent value for these trucks btw) and the “drone” is now exponentially worse when the MDS kicks in. That was my round about way of proving this was exhaust related (It was really just an excuse to buy fun parts for the truck). Coincidentally, I was also recently told my hearing threshold for lower frequencies is unusually high which probably explains part of this.

I poked around through a few GM forums to see if their DOD/AFM had similar drone in 4-banger mode. GM installs a spring loaded “flapper valve” in the exhaust of their newer trucks to combat this issue. Faurecia makes the valve and it’s marketed as a light weight method (compared to adding resonators etc.) of dealing with standing wave/low frequency resonance. Borla makes the GM Performance exhaust for these trucks which incorporates a similar valve (google Borla Pocket Valve if you’re interested) and a lot of guys swear these are totally drone free systems that still sound pretty mean. It looks like their platforms utilizing the LS/LT motors (Camaro, Corvette etc.) have also incorporated electronic active exhaust valves which work with the multi-displacement systems to reduce low frequency drone. Coming back to the Mopar side of things, Chrysler has used the same spring loaded flapper concept on various vehicles through the 2010’s (trucks with a 6.4 hemi being one of them) and I would assume the active exhaust valves in the Challengers/Chargers etc. work with the MDS system to cut down drone. A lot of people are against the spring valves as it’s seen as a restriction (they also seem to squeak/rattle a lot of the time) so I guess it depends what you’re trying to achieve.

Anyways, just thought I’d share this as general food for thought. I have a project in the works as an alternative to using a J-pipe on an aftermarket exhaust and will update on any success/failure I find in the process.


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[shadowhawk]

there are a few mods to drone elimination. I've seen a j-pipe added to the exhaust flow, or the bypass mod. I have a magnaflow that drones at 1700 rpm doing about 75-80 mph on the interstate