From what I read on the net Chevy had no issues. I think that maybe the 5th gear nut issue was caused by the Cummins harmonics which caused the nut to back off. One sharp guy asked why didn't they simply put reverse threads on the shaft which would cause the nut to tighten?
Some years ago I watched a youtube, guy had a new 2001, 2500, 360 gas engine, NV4500 with 75 miles on it, fifth gear fell off. He wanted a new transmission under warranty, dealer refused only offering a rebuilt. He bought a new NV4500 and installed it over a mother's day weekend. I looked for this video again a few years ago but couldn't find it again. I think the gas engines had less issues but still had problems.
Robert