I have a peavey T-20 with a fretless neck , but the Truss rod in the neck is stripped or something. You can adjust it to where the bass plays with nice low action, but it wont stay adjusted..it returns to high action. Can this truss rod be fixed? I dont see anyway to get to it. Can i the truss rod be pulled out from the neck and fixed or is the neck a goner?? Thanks!