My 4500 started acting funny tonight hard shift all of sudden almost will not go into gear,totaly refused to go into reverse shut the truck off and shifted it to reverse and pulled alittle when restarted the clutch master cyl was full when checked any ideas?

 

pullthe dust cover off the bottom and look and see if your clutch is releasing check your linkage out how long has this clutch been in there and have you noticed it slipping before
and i forgot have somebody there to push in your clutch pedal while doing all this