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Discussion Starter #1
If I go up a slight hill and give it a little throttle, it shudders or feels like a tire out of balance. It does this in 4th, 5th, and 6th gear. It does this if it is in tow / haul mode. It does this it I set max gear to 5.

Took it to the dealer multiple times. One time they didn't bother taking it for a ride. Another time I rode with the mechanic, he said this is a common problem and I may have to live with it (NOT). They also flashed a TSB for complaints about shudder, but it doesn't seem to have done much.

The dealer blames the MDS. I think the MDS should be more of a vibration then feeling like a unbalanced tire. I drive a 4-cyl car all the time and know what that feels like. They claim MDS runs in 4th, 5th, and 6th even if the shift is limiting it to 5th.

It has had the EGR replacement.

I don't think it is a tire out of balance because if you let off the gas, in 1 second or so it stops and runs fine. If you accelerate harder it stops. This also makes me think it could be a u-joint or a bad EGR valve.

Of course it is much worse when pulling a load or having the 5th wheel attached.

Anyone else seeing this?

Anyone have seen it cured?

Thanks
Sheldon
 

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I've had a similar condition. I almost would describe it as an on/off surging sensation. I've brought it to my dealers attention, had the egr replaced, and so on. It still does it. Honestly I think the cause is the transmission. I don't know if its the torque converter or not but it seems as though engine power is not being delivered to the wheels in a linear fashion.
 

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MDS is disabled when ERS is engaged (the buttons that limit top gear), though tow/haul doesn't disengage MDS.

Curious what it could be as well
 

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Discussion Starter #4
Thunderhorse, That's what everyone here says, that when ERS is engaged, MDS is off. The mechanic said that RAM now always has the MDS engaged. I sure would like a positive way to know. There is an MDS solenoid someplace - I'd like to find it and hook up an LED to see when it is on or off and then show that to the dealer.

Thanks
Sheldon
 

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There's gotta be an easier way; the solenoids are in the block, and flick open and closed based on whether MDS is engaged (high oil pressure to the lifters to drive in the pins and deactivate the lifters) or not (regular oil pressure to the lifters).
 

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Discussion Starter #6
I wonder it the dealers test tool / code flasher tool can give a good indication of the state of MDS. Plus the wires have to go into the block someplace, is there just one MDS relay or one for each cylinder?

Thanks
Sheldon
 

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I am not sure how many there are but since a tuner can disable MDS I imagine a scanner, at least the right one, would be able to tell when its engaged and when not
 

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Discussion Starter #8
I found a site on the web that talks about adding an LED to the wire coming out of the PCM that enables MDS. Has anyone bought a day on tech authority and checked to see if the connectors for the PCM are described and if one wire is labeled MDS?

And if there is such a wire, why can't you add an LED as an indicator?

And if there is such a wire, why can't you just cut it to disable MDS?

Or am I being too simpleminded?
 

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Did you have the TSB solenoid pack replacement done, mine was doing this from 1st to 2nd until this TSB was done.
 

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Does it do it if you use the gear selector and limited it to 5th gear or 6th gear This will not allow MDS to ingage.
 

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This hesitation you're describing, does it primarily happen when you are feathering the throttle to maintain speed and feels like a slight stutter in the transmission? I noticed this recently and wasn't sure what it was. I was initially thinking the the computer was trying to relearn the driving style since I've been playing around with the new Pedal Commander.
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Discussion Starter #14
Yes, primarily while feathering the throttle.

I took it in a while ago and they flashed some code to 'fix' this. For the next week or two it still appeared. Lately I have not noticed it as much. Don't know what happened to make it better
 
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