Maybe I was told wrong, but I remember hearing that guys used to use those on Dodges, behind the Cummins, and had trouble with them breaking. Maybe those cases were rarer than I was led to believe or maybe they redesigned it. The main reason I bring up the 4L80 is because it is so similar to the TH400. I would think most of the things you do to a 400 would work on a 4L80. Maybe Mike could give a better answer. I could be way wrong on this. Also the 4L80 would be a smaller lighter package than a TH400/Gear Vendors OD combo.