I have a 2007 ram 1500, and I got the muffler and resonators cut off, and added an 18" glass pack. When I let my foot off the gas to hold it at a speed or cruise, it lugs and makes a horrible vibrating sound. I have had people tell me it is just downshifting, and some mechanics tell me it is the "auto-adjusting cam" making corrects for what it thinks is engine knock because if the glasspacks. I need help. I can fix it by keeping it accelerated or letting off completely, but it is a serious problem on road trips when using cruise control. Any suggestions will help. thanks!


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Its the MDS. Multiple Displacement System

All 06+ hemis have it, it deactivates 4 cylinders at cruising speed. The huge mufflers and resonators keep it from making the sound. Free flowing exhausts plus MDS equals a sound that only i can describe as a semi truck jake braking under your truck.

The only way to get rid of the noise is to deactivate the MDS using a tuner. Diablosport tuners have the ability, not sure of others but theres a thread about tuners somewhere.

 

what style of 1500? I will disagree that all 06+ hemi have mds as if you have mega cab no all of them do and wasnt an option until I belive either 07 or 08.

 

meant to say all 1500s have it.

mega cabs are based off of 2500 chassis. even the ones branded as a 1500.

2006 was the first year it was introduced, and it is not an option. Its standard on all the 1500s with the hemi.

 

Thanks a lot for this reply! It was very helpful! It is a standard four door, not a mega cab by the way. And yes, it sounds about like a jake brake. I will try your solution and let you know how it goes. Thanks again!

 

Agreed on the MDS. Common issue and everyone hates it