Rear shock upper bolt

It is a stud from the factory. It looks like this:
http://www.ebay.com/itm/Mopar-Dodge...es&vxp=mtr&hash=item4d0c46b567#ht_1460wt_1119
The vice idea won't hurt it. I sometimes use a pipe wrench. There is a slot for an open end wrench, but they don't usually work that great. If you heat the nut, it will make it easier as well.