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Beating a dead horse here, but MDS Disable should be added as a safety feature.

2K views 12 replies 11 participants last post by  Grimass 
#1 ·
Just got back from a long road trip. And I think that MDS is a bit of a safety issue in some situations.

While cruising in some gnarly Downpours (ie. Whiteout type Florida Cloudburst rain) on a major interstate, traffic was slowed to 25-50mph -- AKA MDS Crack zone... While in these situations, anytime I would even slightly roll on the throttle You could feel the MDS _TRY_ to pull you forward, then, once the ECU realized that wouldn't happen MDS would kick off, and the Transmission would down shift. Then WOOOSH! Full Power and a lower gear ... all while plowing thru an inch or two of rushing water... Not fun.

This lead to a few situations that made my bum pucker up. I finally just hit the tow/haul button and putted along for the rest of the storm(s). But, if it wasn't for the forums (and the 1 line blurb in the manual) I would of never known to use TH mode to disable MDS.

Anyways, hate to beat a dead horse here... But Ram -- if you are reading this... TURN OFF MDS WHEN WINDSHIELD WIPERS ARE ON! Or, please, Give us a logical button to do it.
 
#3 ·
Sounds to me like you need to be more sensitive with your foot. My truck doesn't accelerate that sharply when I give it more throttle and MDS goes off. Calling it dangerous is a bit of a stretch.
 
#4 ·
I think it CAN be dangerous. I tried entering busy traffic at about 45 and just kept pushing my foot down to get it to take off so I could merge without a pile up behind me. That was annoying, scary, and puzzling all rolled in one.

I also agree an On/Off switch should have been a no brainer.
 
#5 ·
I wouldn't be mad if there was a MDS off button. so dumb. I bout my tuner mainly to turn off MDS (sucks for the 2013 guys tho)
 
#6 ·
Honestly I think it is something you get used to. I know the 2010 and new guys can't tell when MDS is on but in 09 "Fuel Saver" means mine is active.. not to mention the exhaust.

I have been driving my Ram for two years now and I have a pretty good feel for MDS. Even if it kicks on a lot I know just how much pedal to give it so that I get out of MDS without causing a shift or that sudden pour on of power.

Just my opinion though.
 
#7 ·
Wow! This sounds like an Ecoboost thread.

I know in the early years there were a few problems but they had several flashes to handle the problems and haven't heard much more about it since.

Could it be because of the new 8speed and getting synched?

Personally, never had issues with it, mine is smooth as butter and have driven quite a few Rams and never had any noticeable issues.

Let Chrysler know about your concerns, maybe they are aware of some issues already and hopefully working on it.
 
#8 ·
Wouldn't be so bad if you weren't beating on the wrong horse. :) The MDS isn't the problem its the overdrive and gearing select of the ECU. Its takes the engine less that 0.04 seconds to switch to disable the cylinders and go into MDS mode and just slightly longer to go back to eight when ECU decides its necessary. And the MDS disable is very sensitive and turns off the microsecond the engine load reaches a certain point which is long before you have even noticed the truck isn't responding like you would like it to. The "woosh" you are hearing with "full power" is the ECU deciding engine load is to high at the current RPM/gear so its disabling overdrive and/or downshifting which instantly raises RPM's as engine load is reduced. Which really has nothing to do with the MDS. Get same behavior on non-MDS hemi's with same transmission setup.

People are under the impression that MDS is so evil because they switch into Tow Haul mode (which does disable MDS) and get more responsive truck. The reason truck feels more responsive is that tow haul delays all upshifts so its holds you in a gear longer for better acceleration under load and it downshifts at much higher speeds so it basically changes all your shift points. It also locks out specific gear(s) and/or swaps in a different one in the shift pattern on the transmission and changes torque converter behavior.
 
#10 ·
100% correct, just about any throttle input or tip in shuts the MDS down quick. The transmission and torque converter strategy is geared toward gas mileage and not performance driving. Simply eliminating torque converter lockup at lower speeds seems like a different truck.

Not only are you waiting for it to downshift you are also waiting for the converter to unlock. That doesnt take long but if you pull into traffic and the conditions arent right to downshift/unlock it seems like it takes ages for it to go.

Comparing it to the ecoboost issues which is the engine actually shutting down and going into limp mode (25mph max) and shuttering horribly plus a flashing CEL is not even close.
 
#11 ·
I've had the same problems a few time. My main problem is when I give it gas in MDS, when usually it will turn off and accelerate, but it doesn't and it just bogs down. 99% of the time when this happens its in town.

I've gotten into the habit of switching to 6th when Im in town and out it back into D on the highway.
 
#12 ·
100% correct. However I do understand the frustration with the system until dealing with its idiosyncrasies becomes second nature. The MDS is pretty easy to figure out, the transmission/torque converter issue is a bit more complicated. I'm not sure I have it down, but for the most part, I just manually put it into a gear and things are OK. It would be interesting to know what each selection does as far as transmission and converter are concerned. I saw an engineering write up on that, I'll see if I can find it and share.
 
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