Newb question about transmissions
 

Yes, I will admit, I thought I knew a decent amount about vehicles, but seems I was dead wrong...

First off, I'm a proud owner of a 2005 GMC Sierra CC Z71.
Secondly, I was curious to know what kinda transmission I have in there? I keep reading about the vette servo's and I'm interested in getting one applied to my truck along with other numerous upgrades. Will anyone happily assist me. Thanks!