JD XUV 550 4 wheel drive issues

I was out last week pulling fence post with our 550 when I heard something pop and then a grinding noise. I unhooked the winch from the front and soon noticed there was no tension shifting from 2 wd to 4 wd.

It's like it was locked in the 4 wd position even though the handle was moving.

I also noticed when I got into a bind later that 4wd isn't working and only my rear wheels were spinning.

I've taken the front covers off and doesn't apear any of the shifter cables are broken but the one for the 4wd does seem to be jamed up and won't move.

Any directions to begin checking what's going on?

Thanks