Kansas,
Jay is probably right about the tap root...and to some extent...plant shock...
I tried transplanting a fairly big one about 6 years ago in a nice raised well drained bed and the same thing happened....
Your better getting a smaller one with as much of the root still intact as possible...
Palmettoman z6-Ajax, On
We have many Yucca in the area. I have always hacked them off at ground level, removed the leaves from the lower 8-10" & just planted them in the ground. They root very easy from my experience. Last summer I threw one in the back yard & forgot about it. When I was cleaning up there a month later, it had sent roots down sideways from the base & still alive.
I had to remove one that was covering a cable ped a month ago, Did the same as above & it is still nice & green & looking great.