The M931 military 5th wheel will mate to a civilian trailer, but as Simp stated above, it is unnecessarily tall for a civilian application unless you actually
need the military two-way tilt feature for serious rough terrain hauling.
Pretty unlikely in most scenarios for most of us, so it ends up locked out and only serving to stick the nose of your trailer eight or so inches higher in the air.
The frame on the 931 is the same width as a civilian tractor, so swapping the 5th wheel is usually a bolt-on affair (though you may have to add a few holes!).
I put a Fontaine slider on one of my 931s, and if I recall correctly something like 70% of the existing 931 holes lined up with the 'new' mount.
The swap lowered the nose height of my M129A4 trailer from 13'9" to a hair under 13'1", which made me considerably less stressed hauling that one about!
The other advantage of the lowered plate height was that slight change in angle can make the difference between 14.00s (as mine has) clearing the trailer landing gear in all situations, and not.
On the military plate, my M128 could just catch a tire tread edge under the right circumstances, like turning right into a slightly ramped Walmart parking lot driveway (don't ask me how I found this out, but the foot
will bend.
). I had to strap the tilting feet back when I hauled that trailer until I put the lower civvy hitch on. Just that lowering changed the angle enough to give clearance for the gear, it can no longer touch the tire tread under similar circumstances.
Very helpful if your trailer feet don't have a tilt capacity!
Cheers
