Early Ram autos, specifically the 47RE were prone to failures if they were hot rodded. The 48RE autos were pretty decent. Since mid year 2007 with the introduction of the 6.7L Cummins the 68RFE has been pretty bullet proof.
Early 6.7L Cummins had some emission issues that have largely been resolved with software flashes. Real early Cummina 5.9s had some bolt failures.
Pre about 2010 Ram 4X4s had what is commonly called death wobble. Easy fix using Moog ball joints.
Ram is now the only truck available with three transmission choices plus several rear end ratios.