It has normal threads. If you're trying to get it off, you'll need a special tool. Here's a link showing you how to do it:
http://free-auto-repair-advice.blogs...oltRickI'm a retired ASE Master/L-1 Technician. I still keep current with the latest automotive technology. Visit my blog for cool articles and TSB's:
http://free-auto-repair-advice.blogspot.com