Hardly any truck built today is designed to 'twist' like an M-series tactical. That is why they can handle extreme terrain with a heavy load successfully.
A friend of mine is a great heavy-truck mechanic, and he crawled all over my M54, saying "This thing is really flimsy".
I replied not so, it was designed that way to allow for lots of frame movements without snapping attachment fasteners when loaded fully and traversing horrible terrain. Things that would cause problems with the usual Pete or Ken-W.
I've seen the rears on both deuces and 5T's at almost 90 degrees to each other, still driving over things.
Even The body parts are held on with long bolts and springs, unlike road trucks. Ever wonder why the hood latches on 5-tons fit on a wide rod and not a tiny hole? I've seen the hood over 3" off center whilst off-roading.
To that end, a number of attachments are either bolted and/or riveted to frame flanges on our trucks, like spring hangers, steering stuff, cross members, and even the rear bogey assembly. Done that way on purpose, borne of many hours of research and development at proving grounds.
DG