Merc dealers will have what you need... and may loan/rent it to you. If not, I'm sure someone here on OSO has the exact tool you need to make your alignment perfect.
Out of alinged drives usually eat the couplers or u-joints first. In your case, no coupler so I would think the u-joints would be the first to go... if the drive itself (is the top or bottom going out on you??) is blowing up, I'd be finding a new mechanic.