Where does it say if you do decide to change fluid/pan/filter at some point on your Ram's 8spd it WILL void your warranty?
Fact of the matter is, a transmission will fail at some point due to lack of fluid changes. It's how these things work today. It's not like the 2 or 3 spd autos from the 50s thru the 80s. These transmissions were purely mechanical beasts and typically the car would fall apart long before the AT would.
Today's ATs run hotter and are loaded with solenoids, small passages and electronics that rely on very clean fluid. Bearings, bushings and seals get beat up as more and more solids circulate around in the factory ATF. Is it likely our 8spds will make it to 100-125K miles? Most likely. I find it funny that 100-125K is considered high mileage. I know guys who consider that new! LOL.
The manual states that the fluid is lifetime. It isn't only Ram that indicates that the fluid is lifetime, Audi does and many others.
The problem is, these trans are very specific to fluid levels and the filling procedures are very difficult. If a manual states it is lifetime, an you change it you are going against their recommendations. Since they try to find reasons to not pay for warranty/service contract work, you run the risk of them refusing to pay for not following their recommendations. This my be true, even if you bring it to the dealership (since they advise against doing the work, but will do whatever you want done, i.e. lifts, exhaust,...).
If you are out of warranty, do what you feel is best, but if you have MaxCare (which is what this thread is about), you might want to consider following their recommendations since they are footing the bill in the unlikely event of failure.