As far as we know, he’s not going to be hunting mutants, but Sentinel Prime has recently been revealed on the cover of the upcoming Empire Magazine, with scans provided via TFW2005.  The character is described as “a big brother and mentor to Optimus Prime.”  There’s reportedly also a new Decepticon named Dreadbox, who gets around as a Ferrari.  There are some spoilers that are provided by a TFW2005 board member that you can check out by clicking the link.  You can also click the images below to enlarge.

Transformers: Dark of the Moon comes out on July 1st.