Originally Posted by 2000max
I was going to say you should try and double nut it but you may have already trashed the threads using the vice grip.
Yea I was thinking the same thing.
If you still have good thread left. Try putting two nuts on the stud. You then tighten the two nuts against each other. Then use the locked nuts to loosen the stud with a normal box end wrench.
Hope that helps.