B3200 lower PTO doesn't spin and makes a grinding noise.

[istrumit]

On my B3200, the lower (underneath) PTO does not spin. When I engage it, it makes a grinding noise, but does not move.

This happened while I was mowing. I heard a strange noise and the mower deck stopped.

I am assuming the transmission is damaged, but I dont know how to confirm or determine what I need to do to diagnose and fix.

Help !