I did the sameat the dealer. they said it was the way the exhaust is flowing during mds and the factory installed resonator. I was just wondering about exhaust options.

 

They must have changed the exhaust for 10?
Did they not have a recall in 09 for the Laramie to put on a quiet muffler? Maybe they went quiet on all of them? Who knows this stuff?

 

Must be something new because I absolutely can't hear or feel anything when my truck kills half the cylinders. RPM's hardly fluctuate either. I always thought people who said they could hear their MDS kicking in were nuts. I guess maybe there's something to it after all.

 

I have an 09 Hemi with 2200 miles on it. 400 miles of those were a trip up the interstate. Whether driving around town or on the interstate with cruise, my MDS kicks on and off seemlessly. No vibration, RPM change, or engine noise of any kind. If I wasn't watching the EVIC I wouldn't even notice. I'm not sure what you are describing is normal for the MDS.

 

I've only ever driven mine, but when the MDS kicks in there is a slight vibration and it sounds like a distant exhaust brake. It's not bad, but I can definitly tell when it goes into 4 cyl mode without seeing the light.

 

Those of you that can hear it, do you have singe or factory dual exhaust?

 

Mine is single exhaust (SLT, all factory parts)

 

Mine is an SLT single exhaust. That is why I was thinking duals may help. Mine is pretty loud if you hit the mark just right. Any other help would be helpful. Mine was manufactured 10-08!!! No light ever comes on when it shifts into 4 cyl. mode. But theroar and vibration can be heard.

 

It's going to chug when it's running on 4 cylinders. Nothing you can do. It sounds like the motor is lugging, but it's really not. My gas mileage still climbs even though it sounds like the motor is laboring. As for doing it while accelerating, the truck will go into MDS under light accel... I live at the bottom of a steep hill and by the time I get half way up doing 25 mph, it's in MDS. There will be a loud, brief "GRRR" as described in the original post when MDS engages, followed by the chugging. Normal MDS operation, in my opinion. Why would anyone want to disable MDS? Who doesn't want to get 20+ mpg on the highway?

 

The RRT for the 09 Laramie muffler was only replace the muffler if there was a rattle in it.