Grizzstang pretty much listed it. There are a number of videos on Y/T that explain how to test Ball Joints and Bearing/Hub assemblies to zero in on the problem. Pretty much what you did with a little more look-see on various components. The lower ball joint should have no more than .5mm (1/32") of up/down movement in it.
The bearing/hub assembly should have zero freeplay. They can be a real bugger to change, if they get siezed in ..as per some recent posts (scroll down and you'll see recent posts). But check with your local parts store to see if they rent out a hub puller tool. The right tool can make a very hard job a lot easier. And shops know how to deal with them.
Another very common failure are the upper control arm balljoints. Not just on Rams but other trucks too. There's also the possibility of a prematurely worn suspension bushing. Someone will just have to put their eyes on the parts.
Sorry to hear of the early demise. None of that stuff is cheap to change. Wear of both the UCA & Wheel bearing/hub assemblies are greatly accelerated running oversized tires and/or really rough winter roads, potholes, etc. We had a really rough road near us, and a buddy's Suburban wore it's ball joints out in one winter ..commuting to work!!
The best is to replace with top quality components such as SKF/TRW/Moog etc. Or Mopar is obviously great.
