Originally Posted by glitzbd
Eco simply means your throttle input is less than 20%. I remember reading this a while ago. Where as MDS has certain parameters that must be met for engaging. So while Eco can be on, it doesn't necessarily mean that MDS is on. However, I do not believe that MDS can be on, and Eco not be lit up.
It is worth noting that I believe MDS will only be on in 0 torque situations (flat surfaces, ie. not pulling a grade, little-no acceleration). Admittedly, I don't have a way to describe it better than that, although 0 torque may not be the appropriate term.
It almost seems to particular, Dodge should offer three settings for all MDS equipped models:
Eco - finds the tallest gear faster and keeps MDS longer (over slight grades, idles when warm in MDS and accelerates in MDS under slight throttle application such as driving at low speeds in a parking lot.
Normal - Which is the current application we now know. MDS activates only during constant speed, slowing down, etc
Tow Haul - Same Tow Haul setting we know now (late shift changes, etc)