That is what I did last fall. Used a 5x5 tube with a hole for the hitch & a 5th wheel pin welded under it to fit the semi. Lowers the other end a LOT.. BUT TAKE THE SWINGAWAY OFF.  Augers don't like  the swingaway bouncing down the highway at speed.  I towed a 13x112 500 miles last fall home with a semi, pickup would be a poor choice. I had a truck axle with a saddle that I used under the back so the axles came out to get it under 12 feet. ... Came home @ 55-65.

A heavy duty car trailer would work also under the axel..