If you look in the hydro fluid reservoir, is there any metal shavings? If so I would pull the pump assembly off and tear it apart and see what parts failed.
Also check to make sure the pulley on the bottom of the pump is moving. There might be a keyway that snapped so it would just be spinning the pulley and not the pump.
That's a expensive repair. Check with a local hydraulic shop. They can rebuild them. There might not be a rebuild kit available but you can buy all the parts individually to rebuild it.