Kenneth,

Most hydraulic valve assemblies have two pressure relief valves. The lift is set higher than the tilt, (auxiliary functions). Due you have side shift function? If so hold it in pressure relief and operate the tilt function. Does it tilt correctly? If so suspect valve spool, seals in the spool, blocked line or fitting. Remove both hydraulic lines from the tilt cylinder, be sure nothing will fall or swing and hit anyone or anything. If not sure, suggest getting a qualified technician to test system. Move the tilt cylinder by hand if possible. Should it move easy, internal seals are worn out. Good Luck.