Irwin makes them in a handy little kit that comes with the matching drill bit. The bellhousing is aluminum, so the broken stud should come out pretty easily. Just soak it in PB blaster penetrant for a good 20 minutes before you start. The extractor kits are sold at about every autoparts store in existence. I havent ever had a start bolt or stud break, but im pretty sure its aimed at a good enough angle to get a drill in there. Just take the broken stud and get a bolt that is the same thread to replace it. The studs back out many times anyway, and ive seen many zs running around with 2 bolts instead of the stud.