How do you turn off MDS?

[KrisK]

the issue with leaving the MDS active whether towing or not, is the constant on off. i wouldnt believe MDS activating and Deactivating is good for the truck, valves, cylinders and pistons.

With MDS active it will constantly come on and then i power out of it, momentarily deactivating cylinders, then going full power.

MDS will activate/deactivate 1 million times in a 15 minute drive. Im in flat south Florida, i could only imagine constant elevation changes and how often that MDS will mess with you....
now if you truly drive like a grandma, you may not notice it ever.

I can’t speak to whether the MDS Is bad for the engine, but mine does switch seamlessly between 4 and 8 cylinder mode.

I will say, the harder I drive the truck, the less the MDS activates.

 

[Ratket]

Guys with the pedal commander on their 6.4 say it improves the drive ability 10 fold, which I can believe due to the throttle delay. And guys with programers with custom tunes also swear by that set up as well, which I also believe because like any manufacturer, they always leave a ton of performance and fine tuning
on the table to be had.

 

[Megazor]

As other have said, MDS can be annoying depending on the situation. I generally notice it is on by the increase in vibration. If I have a drink in the cup holders the fluid will swirl around. Guess that's a bonus free mix. I've had two front driver side body mounts replaced, which made the MDS vibrations more noticeable.

I can't remember it ever turning on with either manual gear select set to 6th or tow haul on. Next time I get to steal the truck back from the wife, I'll see if I can get MDS to turn on in tow/haul.

On a side note, when the truck was new, there was a easily heard squeaky kind of sound from the truck when MDS was on.

 

[blade]

diablo trinity2 ex bro

 

[marks146]

In my 2015 the MDS is a PTA. It shifts in and out sluggishly. On hills you tend to lose momentum, so I shift into 5th and put it into trailer mode. Problem resolved. I do wish there was an on/off dash switch.

 

[SouthTexan]

In my 2015 the MDS is a PTA. It shifts in and out sluggishly. On hills you tend to lose momentum, so I shift into 5th and put it into trailer mode. Problem resolved. I do wish there was an on/off dash switch.

That would be nice.

 

[Ratket]

I can’t remember if Tow haul locks out 6th gear or locks out Mds.. I know it locks out one or the other but I know it doesn’t do both. It’s been almost a year since I had my 6.4, but I tested it endlessly to figure out what did what. Simplest way to tell is set that cruise at 60 and see.
Manual gear selection locks out mds if I remember correctly so Tow haul should lock out 6th? I definitely remember Tow haul locks out one and manual gear selection mode locks out the other, but no one function disables both at the same time.

 

[m25443]

I can’t remember if Tow haul locks out 6th gear or locks out Mds.. I know it locks out one or the other but I know it doesn’t do both. It’s been almost a year since I had my 6.4, but I tested it endlessly to figure out what did what. Simplest way to tell is set that cruise at 60 and see.
Manual gear selection locks out mds if I remember correctly so Tow haul should lock out 6th? I definitely remember Tow haul locks out one and manual gear selection mode locks out the other, but no one function disables both at the same time.

Tow/Haul does NOT deactivate MDS in the 2014+ 6.4. Common misconception.

 

[Ratket]

^ That’s what I thought- so it does lock out 6th. And Manual gear selection locks out MDS.

 

[Jeff Courtney]

'18 3500 SRW 6.4 . MDS is annoying. When wanting to apply light throttle that I feel should be enough for conditions and no response apply more then truck over accelerates. Like a delayed reaction. Annoying

 

[SouthTexan]

I am half temped to make a poll of those who like/dislike MDS. I wonder if Ram did the same before they decided to add MDS to the HD. Although they probably don't have a choice given the new CAFE requirements coming to the class 2b and up trucks in a few years which were previously except. Regardless, they should offer a way to turn it off permanently turn it off in the menu section or with a button.

And by permanently I mean it turns off regardless if you stop/start your engine and will not come on again until you select it to come on. If they could do the same with the exhaust brake on the Cummins that would be great. Hint hint @ramcares....

 

[mohemipar]

Regardless, they should offer a way to turn it off permanently turn it off in the menu section or with a button.

And by permanently I mean it turns off regardless if you stop/start your engine and will not come on again until you select it to come on. @ramcares....

Exactly right. Its certainly not difficult to use the Manual mode but it just gets old. And if you shift to reverse and then back to drive it erases manual mode and you have to do it over again. I've gotten so used to doing it I can do it in about 3 seconds with my eyes closed now. But a button to turn it off permanently until pushed again would be awesome!! Maybe the new HDs with ZF trans will offer this but I won't hold my breath.

Although they probably don't have a choice given the new CAFE requirements coming to the class 2b and up trucks in a few years which were previously except. @ramcares....

Good point.

I use the MDS when on long trips and I really don't know how much it helps because I've never done any experiments. But when the truck was totally stock and brand new it managed around 17 (said 17.8 on the make you feel better-meter) on a long trip. I don't know how much weight was in it but hardly anything, just a couple people and gear. Hills/mountains and wind/storms really start to hurt. A combination of them and you might as well be leaking gas.

If you are regularly doing long trips the Cummins would be real nice to have.

 

[Fitz-0518]

In our the 2018 2500 6.4 66RFE. Around town we use gear select 6 to keep out of MDS. When towing we "thought" selecting tow haul disabled. It does not. Must use both gear select with tow haul selection to keep it out of MDS. Frankly, we found the gas savings difference insignificant. My view, the long term mechanical effect of 4 cylinders dragging the other 4 cylinders thru the the rotating air, fuel spark sequence cannot be good for a combustion engine. Grateful that the RAM engineers gave us a way to disable.