as old said.
does it have oil?
is the pump actually turning with the drive shaft?
pump cracked / lines split?
if pump is turing, shut down and take input line to vlve off and aim in bucket and see if pump is making flow.
if yes, shut down and hook back up..
take the return to tank line off and ai'm into bucket and start tractor.. now try to lift loader. oil should be diverted to the lift cyl, and not have oil bypassing the valve or relief .. if you get oil inthe bucket.. either relief is stuck or spool is bypassing.
post back more details.