MDS question

Jerrybob said:

To each their own....I am too old for that loud crap....I want smooth and quiet....like a good whiskey by the campfire. If too loud.....I take out my hearing aids.

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Rt71668 said:

Please forgive my ignorance. Ok so I just realized that my 2017 1500 which I purchased brand new late 2017 came with the hemi 5.7 Mds Vvt. Now for the life of me I cannot find anything that would indicate that I actually have that engine in my truck !! Is it possible that the engine I paid an additional $1500 for is not the actual engine I have ? My truck was also supposed to come with the sport hood which it did not. That I realized right away and it was changed by the dealer. TIA.

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Wild one said:

If it's got a V8 it's the 5.7 Hemi with VVT and MDS.There's 3 motors available for the 1500's,2 are gas,one is diesal.You have the little 3.6 V6 Pentastar,then there's the VVT/MDS equipped 5.7 Hemi ,and the little 3.0L EcoDiesal.Up till 2013 there was one more gas V8 available and that was the little 4.7,but it was discontinued long before your truck was made

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Rt71668 said:

Wouldn’t i notice if I had it ? Not to mention get better gas mileage lol. Wouldn’t there be a light or a switch ?

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Wild one said:

There is what's called the "eco" light,but it doesn't really mean much as far as whether or not the MDS is kicked in,all it means is you are driving in an economical manner,and that light can be turned off or on if you go through the settings on the radio.If you listen close you should be able to hear and sort of feel it go into MDS mode,it's more noticeable if you have an aftermarket muffler/exhaust,but if your really tuned into your truck,even with the stock exhaust you can still tell when it drops cylinders for the MDS.You can bypass the MDS by shifting the truck into 8th gear via the buttons on the steering wheel,it'll still downshift and go through all the gears,but it locks out the MDS mode. VVT you'll never feel as VVT stands for variable valve timing and is done via solenoids etc.

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Rt71668 said:

Yeah that’s what I thought and I’ve never seen that eco light ever come on and I do have a catback and know even vibration my trucks has ! Thanks to of course my OCD lol. This is why I’m so confused how could my truck not have it if it’s in every 5.7 hemi ?

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Wild one said:

If you bought the truck new,and it's never been tuned to turn the MDS off,you have MDS. All of the 5.7's in the 1500's have MDS,it's not optional,lol

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Wild one said:

If you bought the truck new,and it's never been tuned to turn the MDS off,you have MDS. All of the 5.7's in the 1500's have MDS,it's not optional,lol

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Rt71668 said:

Weird because I paid extra for it ! There is zero chance my engine goes into 4 cylinder mode and there is definitely no eco light !

View attachment 193531

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OCDTech said:

The MDS, especially on the newer trucks, cannot be felt. Pretty seamless.

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Wild one said:

It's not the MDS or VVT that's optional and you paid for,it's the 5.7 engine itself that's optional,lol. The only way you can defete the MDS is shift the tranny manually via the ERS/steering wheel buttons,if you drive around with the truck showing 8 on the dash,the MDS won't kick in. Trust me you have MDS and VVT on your truck if you have a V8,as the only 8 cylinder available in the later 1500's is the 5.7 with both. The earlier 5.7's in the 2500's didn't have MDS,but I think since 2014 they've had the MDS system to.The only 5.7's available with-out MDS are the 6 speed manual transmission equipped Challengers,and I doubt you have a 6 sp Challenger motor in your 1500,lol

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Rt71668 said:

Really and no light or on/off in settings ?

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OCDTech said:

@Wild one said in post above up there, that there is an ECO light, in the newer trucks you can turn it off, yours may be off, HOWEVER the Eco light DOES NOT indicate that the MDS is on. The ECO light is only to let you know your driving efficiently.

Also i do not know what year they offered the on off feature, not mine for sure.

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Rt71668 said:

Mine is a 17’ and definitely doesn’t have the light

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RVGuy said:

Then it's turned off in the settings. They all have the light in the cluster. The eco light does not indicate MDS as being on or off, it's just a glorified vacuum gauge to tell you if you're driving nice or not.

All 5.7 Hemis in the 1500 have MDS, the 5.7 in the 2500 or 3500 do not have MDS, the 6.4 in the 2500 or 3500 does have MDS. The only way to turn off MDS without a tune is to manually select a gear with the +/- buttons either on the steering wheel or column shifter depending on your transmission. Some trucks the MDS really is seamless, some it isn't. Some catback systems keep the MDS seamless, some don't. Yours may just be seamless if you can't tell. I have an aftermarket muffler and I genuinely can't tell when mine kicks in on the highway but I can tell at town speeds.

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OCDTech said:

This is a quote from @Tach_tech

In the radio settings screen it will be called “Fuel Saver”. That turns on/off the eco light. Some radio software versions had the option omitted. There was an update to fix that awhile ago. Check for any radio updates.

As well eco doesn’t always mean MDS is activated. All it means is you’re driving in a eco manner. Usually MDS will be activated but not always.

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Rt71668 said:

Wow thx guys for all the helpful info ! Maybe I’m lucky I don’t have the light it would mess with my ocd lol

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