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Disabling MDS Per Ram Engineers

133K views 143 replies 105 participants last post by  2015 5.7 4x4 
#1 ·
This is direct from the chat with the Ram Hemi Engineers.

To disable the MDS, put your shifter from D to 5 (as displayed on the EVIC or cluster). With the console shifter, this is just one hit to the left. With the column shifter you need to push the +- button - one time.

Your trans will still shift up and down automatically through all the gears.

Tow/haul button is not the correct method.
 
#4 ·
It will automatically downshift and upshift to the highest gear you have selected.
 
#10 ·
Yes. Just set the shifter so the 5 is showing and leave it there. The trans will downshift and upshift all by itself. If it set at a lower number, say 3 for instance that is the highest gear you will be able to attain without manually moving it up.
 
#11 ·
for some reason I don't think thats right on an 08..tow button still allows the MDS function..or at least I've read this on the forums from these sites. I do use the tow button almost all the time and it still goes into this ' flat 'spot that makes me push the gas a little bit harder to make it move with less lug when I need it...
 
#16 ·
This is correct, There is no MDS with the tow mod or OD on a 08 ,the risen you have to hit the gas a little harder sometimes is when it hit in that 5th gear and when you try to accelerate it takes a good push down on the gas to kick it down.
 
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#20 ·
That's not quite correct. Fifth is an actual gear. Putting it in manual mode takes away the MDS. Hitting the Tow/haul button takes off O/D which is electronic.

This is for those that have the ability to switch to a manual shift mode. If your Ram doesn't have that option, then I do not know how to turn off the MDS.

I originally thought using the Tow/haul button did it but was corrected during the Engineer chat which I why I made the original post in this thread.
 
#15 ·
Nope. I originally thought the tow-haul method turned off the MDS too. But when I attended the Engineer chat I learned the correct way to do it without using a programmer like the Predator.
 
#21 ·
So let me understand this, if I push the minus and plus symbol at the same time after I put manually put it in 5th it will shift normally. Can you shift it manually to 5th gear when your in park? Ive been manually getting it to the max gear I want then hitting the tow button. This shifts like you mention. Just manually shifting by itself is kinda cool also, escpecially if your getting on it. If this is wrong please clarify.
 
#22 ·
If you put it in 5th and leave it there, it will shift down to 1 and up to that gear all by itself. You just won't see the number change on the display. But it disables the MDS according to the Engineers.
 
#23 ·
Has anyone tried to find out what their fuel mileage is with and without MDS? Just curious. I have a very short commute and I get 10 mpg. The MDS seems like a joke in SouthWestern PA with it's endless hills. I'm going to track my mileage on the next tank and see what happens. Good info RootBeer!
 
#26 ·
The difference is slightly lower mpg's without MDS, but not enough for me to go back to it. Frankly I hate it. The truck seems sluggish and the drone is a PITA.

Dont Want To Sound Stupid But What Is The MDS???
It automatically disables 4 cylinders to save gas. It might get you an extra 1-2 mpg.
 
#24 ·
I did the other day going to the VAMC in Mpls, MN. It is about 196 mile round trip and going up I shut MDS off using the +/- 5th gear setting. According to the EVIC I averaged 16.3 mpg and it was 8 degrees out and I ran 70 all the way. On the return trip I reset the gas mileage and drove with MDS on and received a 14.8 mpg, the temperature was 12 degrees when I drove home. All I can say is the truck feels more responsive and doesn't get any drone in the exhaust with MDS shut off. By the way this is the best mileage I have gotten all winter by shutting off the MDS as I alway ran it before. I also notice a 250 rpm difference between MDS and no MDS at 70 mph. If I were to run at 55 mph then the mpg's go way up but that is not my driving style.
 
#28 ·
Reading all this makes me happy that I could not afford to get a 5.7 Hemi. All I hear is how crappy it is and how it doesn't save you any gas mileage. You'd think that Dodge would make MDS an option not standard. Or perhaps install an easy button on the dash that turns it on and off just like the tow/haul button.

I wonder how may tuners are going up for sale now that this info is out??
 
#29 · (Edited)
Ummm I still love my Hemi, and I'm sure everyone else that has one does too. It's not the Hemi that sucks, it's the MDS. And you CAN disable it if you want without buying a tuner. Also, the MDS does save gas mileage. I'd rather have the Hemi over any other RAM engine. I seriously would have been disappointed if I bought the 4.7.
 
#31 ·
Me, I like the MDS!
Unless you have a loud exhaust, you'll never hear a drone. (24" Mufflex here, no drone)
It's flat here in Houston, can easily stay in 4 mode for most of my work commute.
I've experienced 27.2 and 28.1 MPG on the freeway 'locked' in MDS mode. Will we all get results like that? Of course not, but it does show the potential of the MDS system.
Those of you who don't like MDS should be happy all it takes to disable it is one click of the button on your shifter.
 
#37 · (Edited)
Been experimenting with disabling the MDS with the manual shifting into 5th and here's what I found. Definitely works and appears converter does still lock up but there is about a 200rpm difference between the lockup in auto and lockup with the gear selector in 5th position (Total converter slippage looks to be around 500rpm which is about what I used to see with my trailblazer). Converter definitely locks in either position but there is 200rpm less slippage in auto position. Almost like the converter doesn't completely lock if gear selector is pulled into the 5th position. Also the gas mileage is almost a push. Not real impressed at this point with the MDS. Mine was showing around 18-20mpg on flat terrain with mds active or disabled. Drives smoother with the MDS disabled too. Just my .02...
 
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