How do you turn off MDS?

[SouthTexan]

Friend of mine with a 6.4L 2500 Tradesman wants to turn off MDS or select when it comes on. We were towing his boat down to Port O'Connor this past weekend and it was definitely noticeable in how the engine sounded in 4 cylinder mode. I told him I did not know, but I know a great group of guys that probably do.

Does he need a tuner or is their a way to do it in the options menus?

 

[22hemi13]

Friend of mine with a 6.4L 2500 Tradesman wants to turn off MDS or select when it comes on. We were towing his boat down to Port O'Connor this past weekend and it was definitely noticeable in how the engine sounded in 4 cylinder mode. I told him I did not know, but I know a great group of guys that probably do.

Does he need a tuner or is their a way to do it in the options menus?

If it’s like the 5.7 just put it into manual mode. Or tow haul mode.

 

[SouthTexan]

If it’s like the 5.7 just put it into manual mode. Or tow haul mode.

He said it still comes on in Tow/Haul mode although not as much.

 

[pwjouster]

it has never come on for me in tow haul mode.

use the manual shifter to lockout in 6th gear. gives you the full range of gears, but MDS will not activate.
i do both 6th gear and Tow mode to give the truck better pep, shifting speed, and hold out higher RPM.

changes the truck into they way it should be tuned...minus the excessively hard shifts

 

[SouthTexan]

it has never come on for me in tow haul mode.

use the manual shifter to lockout in 6th gear. gives you the full range of gears, but MDS will not activate.
i do both 6th gear and Tow mode to give the truck better pep, shifting speed, and hold out higher RPM.

changes the truck into they way it should be tuned...minus the excessively hard shifts

That is what he said. He did not have it in tow/haul mode when we were towing his boat.

Not sure why I didn't think of the gear selector turning off MDS. I will let him know. Thanks.

 

[ronheater70]

So, WHY turn it off? I mean if your towing, you're on the throttle and MDS isn't kicking in anyway. whether in tow/haul or not, or shifting manually. If you get a downhill or a level place and dont have much load it may kick in, but whats the big deal with that, doesnt hurt anything. I never got the MDs hoopla when ihad my 6.4. Never bothered me any, In fact I tried to get it to kick in more often!

 

[SouthTexan]

My friend lives in the Texas hill country where there is a lot of constant up and down driving. He said on flat roads it is fine. However, when he is in the hills it is a PITA because it goes into 4 cylinder mode down hill and takes while to go back to eight cylinders going up hill which causes him to loose momentum. I am just going by what he is telling me, but I can see how this would be a pain where he lives.

 

[turkeybird56]

Hmmmmm, guess personal preference. MDS is OK, though I am not a big fan, just lock out in manual shift mode. If on highway, I leave alone but in town, I always manual select. Again, just personal preference..

As told above, to lock out put in manual gear select. Now MDS does not operate when in tow haul mode, at least it does not on MY 19 5.7 Hemi...and it did not on MY 15 ED. I do not know if the 6.4's are set up different or not, just saying, all IMHO

 

[22hemi13]

My friend lives in the Texas hill country where there is a lot constant of up and down driving. He said on flat roads it is fine. However, when he is in the hills it is a PITA because it goes into 4 cylinder mode down hill and takes while to go back to eight cylinders going up hill which causes him to loose momentum. I am just going by what he is telling me, but I can see how this would be a pain where he lives.

Texas hill country is tough. I know!!! My 5.7 don’t have mds which is nice. But if I’m towing and get stuck behind somebody it’s an exhausting trip.

 

[SouthTexan]

Texas hill country is tough. I know!!! My 5.7 don’t have mds which is nice. But if I’m towing and get stuck behind somebody it’s an exhausting trip.

Yeah, everyone's driving situation is different. Heck, I even had to switch tunes when I was staying the week up there.

I usually have my Hardway tune when unloaded because it generally shifts sooner and keeps the rpms low for a calm drive. This is fine for where I line, but did not cut the mustard in the hill country. Yeah, my Cummins was able to oull up any hill in the 6th gear at 1,200 rpm doing 55 mph, but it felt like it was starting to lug so I had to remove 6th. I eventually got tired of it and loaded my Anarchy tune which I generally use for towing since it shifts later to keep the rpms above 1,600.

That tune was perfect for that type of driving. Although it kind of makes sense since Anarchy Diesel's shop is located in the hills of Tennessee while Hardway is located in flat land off the coast of Florida. Both tunes were made in different types of driving conditions.

 

[bigbuck92]

Not to derail the thread, but texan when you run your tunes do you still put it in tow haul mode? or does tuning eliminate the need for it? Also which is better for gas mileage? A constant 1600-1800 rpm, or a 12-1400 with some shifting when needed? Sorry for going off topic. lol

 

[SouthTexan]

I put it in tow/haul with both tunes to take advantage of the torque converter locking a gears sooner.

Without tow/haul mode, the Hardway will lock up in 4th and the Anarchy will lock up in 3rd. With tow/haul mode, the Hardway will lock up in third and the Anarchy will lock up in 2nd. The Anarchy tune doesn't really shift any different between modes, but the Hardway tune does. The Hardway will shift a little higher in the rpms, but it's downfall is that it holds on to gears to long.

For example, it will shift into 6th at 55 mph and will hold on to it until you get below 45 mph when you are at around 950 rpm. This is okay unloaded and the truck has enough torque at that rpm to slowly accelerate even up slight hills, but this is not good when towing. When not towing, these low rpms are perfect for my kind of driving and better fuel mileage. Which is why I get about .5-1 mpg better with the Hardway than the Anarchy.

 

[KrisK]

My friend lives in the Texas hill country where there is a lot of constant up and down driving. He said on flat roads it is fine. However, when he is in the hills it is a PITA because it goes into 4 cylinder mode down hill and takes while to go back to eight cylinders going up hill which causes him to loose momentum. I am just going by what he is telling me, but I can see how this would be a pain where he lives.

I can only speak from experience with my truck as it's the only 6.4 I've driven, but mine switches back to 8 cylinder mode almost immediately upon starting up a hill. It switches before I can detect a change in speed or see any change to the speedometer. I've had no problems with it switching back and forth and causing me to lose momentum. When I tow, I don't recall it ever switching to 4 cylinder mode. I don't have any custom tune. It sounds like his MDS may not be working properly if there is a lag in it switching out of 4 cylinder mode.

I guess I should add mine is a 2017 Ram 2500. It's quite possible the MDS functions differently in other year models.

 

[McBroom]

My 18 is having a similar issue.
When it started missing the mds quit working at the same time. It’s an the shop now (day3). They still haven’t figured out what the problem is.


I Love my 18 Ram 2500HD 4x4 CC
Blue Streak Pearl off-road

 

[pwjouster]

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.

 

[Don_T]

I can only speak from experience with my truck as it's the only 6.4 I've driven, but mine switches back to 8 cylinder mode almost immediately upon starting up a hill. It switches before I can detect a change in speed or see any change to the speedometer. I've had no problems with it switching back and forth and causing me to lose momentum. When I tow, I don't recall it ever switching to 4 cylinder mode. I don't have any custom tune. It sounds like his MDS may not be working properly if there is a lag in it switching out of 4 cylinder mode.

I guess I should add mine is a 2017 Ram 2500. It's quite possible the MDS functions differently in other year models.

This is exactily how my MDS works in my ‘18.

 

[SouthTexan]

Maybe my friend's truck is starting to have lifter issues like some of the others who have said their truck lags when switching. I would not think so since the truck has less than 50k.

 

[Ratket]

It’s not having issues, like you said everyone’s driving experience is different.
My 14 6.4 MDs drove me fckn Nuts. Towing or not, if I was some where “ city like, stop and go with a speed limit of 55 or less tow haul was on and gear Spector was locked out in 6th. I did these two things to keep MDs off and keep that tranny from hunting from 2nd/3rd to 5th and 6th which also drove me Nuts. It would typically hold 3rd/4th which made the experience more pleasurable. Once on the hwy I would even leave tow haul on turn off the gear selector to get MDs to activate. MDS will activate while in Tow haul it is just not as frequent. Texan, tell ur buddy to get some 4:56 gears and never look back lol.

 

[SouthTexan]

Lots of good info there. I am not sure if he wants to re-gear just yet though. Thanks!

 

[Alexpaul09]

I have a 2014 6.4 and I hated the mds! Felt sluggish and would randomly down shift. I bought a programmer online and shut it off and put it on a economy tune and it runs way better and much better throttle response