Its funny. I read this post the other day and I thought to myself 'why does everyone hate MDS?!' That very evening I was driving home from work and just as I was slowing down to take a turn the truck jolted for about a half second and the gear selector was suddenly showing "6" when I didn't even touch it and it should not have been in 6th since the speed was so low. Even more curious was that the "i" symbol on the EVIC reminding me of an oil change suddenly disappeared. Everything seemed fine afterwards and the "i" came back upon next startup but pretty weird, eh? No issues since - knock on wood!

Everything is stock on my truck and sure I can notice the MDS sometimes depending on the driving situation but it doesn't really bother me that much, especially local/rural style driving. On the highway I sometimes turn it off with the shifter if I am descending a hill and I feel that the MDS is holding her back a little. Other than that I think it works fairly well for large truck.

Just my 2 cents.

 

I just filled up on Shell 89 octane. Reset MPG and drove rolling two lane 55/60 mph home. About 15 miles. Every time MDS kicked in the MPG world start clicking up. When MDS was off no increase. I got home to the side door of my house showing 22.4! That wouldn't have been with out MDS. Trucks only rated to 20mpg.

 

i have a 12 ram and do notice when mds kicks in but dont find that it's hard to kick out at all in fact i wish it would stay in a little longer sometimes seems that even the slightest grade and she kicks out. if im using cruse control at about 110 kph it almost never kicks in only on a down grade or perfect flat with no wind. if the engine gets loaded slightly while in mds i do notice a slight vibration which is understandable considering it running on half the cyl's

 

Postal,

MDS is pretty touchy but you will reap the benefits after your Hemi breaks in.
The vibration is normal and there is no concern there; like you point out, 4 less cyls to move everything.

Below is taken from page 444 for the 2012 Ram O/M.

"MULTI-DISPLACEMENT SYSTEM (MDS)
(IF EQUIPPED) — 5.7L ENGINE ONLY
This feature offers improved fuel economy by shutting
off four of the engine’s eight cylinders during light load
and cruise conditions. The system is automatic with no
driver inputs or additional driving skills required.
NOTE: The MDS system may take some time to return
to full functionality after a battery disconnect.'

Hope you enjoy your Ram for many years to come.