Hey guys. I've recently started hearing a low hollow vibration sound when I am going very slow. I mostly hear it in town when I am going slowly from redlight to redlight. I'll be going 20-30 MPH at low RPM's and I'll hear the sound. I don't feel anything in the wheel or anything and it seems to go away once I get back up to speed. It may possibly have something to do with my MDS, but I always thought that was the soft fluttering sound I hear at lower RPM's. This vibration sound just doesn't seem right and I've never heard it while driving my mom's hemi. Any ideas as to what this might be or other imput on this? Thanks.

 

At first I was thinking u-joints, but you have an '08. Yup, gotta be the annoying MDS.
hated it since day one. lags on the shifts. F's the tranny shifting all up and it can't even keep these trucks moving at a constant speed ever. Mine would always kick out to speed up and kick back in...repeatedly on the highway.
Great idea, just not meant for large truck IMO.

My Diablo Predator allowed me to disable that feature...result...Much smoother shifting tranny and much quicker, Just like it should have been when i bought it.

 

I dunno if I would blame this on MDS, my thinking is that you are hearing the EGR valve opening and closing, it's amplified once you remove the resonating "Hemi hat" over the TB. A CAI would serve to amplify this a bit more, although your K&N 63 is nowhere near as pronounced as my K&N 77 with it's nice pretty chrome tube makes it.

To me, I don't know if I'd call it a "rattle" per say, I think it sounds like a very rapid pinging sound.

Although whether it's the cause of your rattle or not, I'm in 'dogs camp on my feelings of MDS on a full size truck. I'd get me a tuner and kill the thing anyway, plus have ALL the other benefits. Could be he's on target and it's the cause of your annoying sound, I just don't think so...

 

i dunno Hammer. That could be of issue as well, but my truck would vibrate when in MDS. it would shake my pant legs and tickle my leg hair....lol Especially if you are 1/8th way into the gas just enough to give gas but keep the MDS active.

 

You could be right on target with this, you are in a much better position to make an MDS call than I am, as I never had it in my '04 Hemi (thank God!). Although I've been in many MDS Hemi's and driven a couple, you got a lot more hours in an MDS Hemi than I do.
I just don't really recall hearing any vibration sound in the ones I've been in. Now aftermarket muffler drone, that's another story, LOL...

 

Well, I'd say it's not a vibration sound but more of a reference to vibration for what our brain percieves. it's more of a sound pressure thing through our ears and airborne vibration if you follow. My floor wouldn't vibrate yet my pant legs did. That's airborne, not floorborne. it was very odd.

 

Thanks for the replies guys. I was kinda thinking it might have been the MDS because it would go away after getting back up to normal speed. I think I'll stop by the dealership in town in the next few days and see if I can get the head mechanic to ride with me and see what he thinks just to be sure. I'm thinking Dirtydog may be right though. What he's describing sounds exactly like what I'm talking about. It's a sounds like a vibration, but you don't feel anything. It feels weird. It kinda reminds me of being in a vehicle with subwoofers with really low bass. I would really like a tuner, but I'm a poor college student at the moment. Hopefully later on I'll be able to get one...plus a few other goodies. haha.