I never trust a Dealership any farther than I can pick up the Dealership and throw it. Its sad for the few good Dealerships out there, but just way to many are bad that it tarnishes all of them. There is a reason people call them Stealerships. While all franchises have problems, Chrysler's Dealerships seem to be the worst of the lot. The Dealerships are really dragging down the brand, and the big shake up with the Federal Gov taking over and closing half the Dealerships, on what appears to be political grounds, before FIAT bought the company likely only made it worse.
Did the Dealership perform the Recall/FDCM update? The FDCM software alone is responsible for the Service 4WD light in many cases, but NOT all, the latest software update is suppose to finally fix this problem. They should have performed it regardless if you elected their recommended service or NOT, and it should at least eliminate that as a possible cause.
Google search for what the codes they gave you mean. Find out what c1405, c1406, c140f and c1438 is telling you what is wrong. The shift motor failing is pretty common. As well, leaking oil can get into connectors and cause shorts that will cause codes. Just cleaning the connectors and fixing the oil leak can solve a problem like that.
I agree with Wingdog, based on what you told us, it sounds like the Dealership is trying to rip you off. The chances of the XFR case and Front Diff failing catastrophically, especially in a way to create a catastrophic accident (that is big leap in probabilities, although nothing is impossible) is pretty darn low if those components are NOT making any noise, aren't creating any very noticeable reactions in the drivetrain, aren't getting hot, etc.
So listen and observe if you can hear or notice any of those things, after a long drive, touching the differential carriers, XFR case and Transmission and assessing their temperature will help as well. If one is significantly hotter than the other, that would be a warning sign of something serious.
But find out what the 4 codes mean, they are telling you what the FDCM saw as malfunctions of the 4WD system. Keep in mind the FDCM deduces these things from the inputs it sees through sensors and wiring, so don't jump to conclusions that code means that particular definition is definitely happening and is catastrophic. Something as simple as a shorted or broken wire can or a dirty connector can make a electronic control module conclude a part has totally failed.