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Discussion Starter · #1 ·
i have been playing with the manual shift system on my 2012 CC LONESTAR 2WD and i have found a way to help with gas mileage. if you will choose 6 gear as soon as you shift your truck into drive and leave it there your truck will not go into mds mode and it will not lug at lower speeds which causes the truck to burn more gas. i have been playing with this for about a week now and my mileage has stayed between 14.5 and 14.8 with alot of stop and start driving where before it would fall to around 13.5 to 13.8 or lower. this seems to even get better mileage on the highway also, you would not think so but riding down the road in sixth and shifting up to let mds kick in the instant mileage number will fall. so try this trick and let me know how it works for ya. :smileup::smileup::smileup:
 

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i have been playing with the manual shift system on my 2012 CC LONESTAR 2WD and i have found a way to help with gas mileage. if you will choose 6 gear as soon as you shift your truck into drive and leave it there your truck will not go into mds mode and it will not lug at lower speeds which causes the truck to burn more gas. i have been playing with this for about a week now and my mileage has stayed between 14.5 and 14.8 with alot of stop and start driving where before it would fall to around 13.5 to 13.8 or lower. this seems to even get better mileage on the highway also, you would not think so but riding down the road in sixth and shifting up to let mds kick in the instant mileage number will fall. so try this trick and let me know how it works for ya. :smileup::smileup::smileup:
If that was true, then why in the world would they engineer MDS? I think MDS is meant to save you MPGs on the long haul at steady highway speeds where momentum takes over and you could sustain that speed with less cylinders. Could it be a gimmick?
 

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MDS should be more economical from the stand point that when running on 4 cylinders the throttle plate opens much more and this lower pumping loses across the engine. This is what we hear out of the exhaust since you have 4 cylinders pumping allot more air individually than all 8 would be individually.
 

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Yeah...I'm not sure about this. Only way to be sure is to try though. I will like to keep my MDS since when school starts for me in August I will have a 100+ mile round trip every day. I'm sure it will come in handy. Will have to see how much gas I save if I run at 65 mph rather than the posted 75 mph speed limit.....but then again I always run late so I'll probably be driving at 80-85 and at those speeds there will be no MDS hahaha
 

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I think if you turn on tow haul mode, all it does is turn off the mds
Tow/haul also changes the rpm to a slightly higher level...about 200 rpm in your top gear. That TransEngineer guy on the site also said it changes the shift schedule slightly by keeping it in a given gear just a bit longer than normal...among other things. T/H is more than shutting down MDS.
 

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Discussion Starter · #15 ·
driving to work tonight i thought i would bump the shifter up so the mds would kick in just to see what it would do. I was cruising abiut 60 and shifted up and when mds kicked in the instant mpg went up but began to fluctuate up and down compared to being in sixth with mds off it holds steady so i am thinking the weight of this massive truck is to much for only four cylinders to pull consistintly. Now at lower speeds around 45 kick the mds on and it holds the mpg pretty good. Just what i have found messing around looking for better mpg out of this beast. I will continue to experiment with this project.
 

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I too have been doing this based on my Ram service guy's recommendations.

For about four weeks now, I've been switching off MDS [6th gear] everytime I start the vehicle on and around city driving [stop/start] only.

I have a 2012 Laramie 5.7L 4X4 that, except for a Magnaflow 16869 and 10778 Y-pipe, is pretty much bone stock [I do have a drop-in K&N]

Previously, I would average right around 16MPG in the city [15.5MPG to be exact] per fill on 89-grade fuel. My calculations, based on the last four weeks of driving [without MDS activated], is that now I'm averaging almost 17MPG [16.9MPG to be precise].

Not a difference that's going to allow me to retire anytime soon[er], but could be somewhat significant over the vehicle's life span.

These are hand calculated averages based on fuel consumed/miles driven.... NOT fuel economy based on the vehicle's EVIC.

I'm going to continue for another month [maybe two] to see if further improvements prevail..... and maybe try highway driving too.
 

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Tow/haul also changes the rpm to a slightly higher level...about 200 rpm in your top gear. That TransEngineer guy on the site also said it changes the shift schedule slightly by keeping it in a given gear just a bit longer than normal...among other things. T/H is more than shutting down MDS.
Good to know, thanks
 

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I just don't really see how disabling MDS would increase gas mileage. The only thing I could guess would be that without MDS on, the power of 8 cylinders is readily available, so maybe there would be less downshifting, therefore keeping rpms down.

I still think if you're seeing MPG increases, especially at this time of year, that your gas station has switched back to summer blend fuel and that is the reason for your better MPG.
 

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Assuming this is true, the conclusion we can come to is that maybe what works well (improves mileage) on a 2WD single cab does not work well on a heavier 4WD crew cab. Especially if it has bigger wheels and tires.
 
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