from twitter from tyrese.. if posted lock please Lots of Photos and Videos from Chicago Set of Transformers 3 | WorstPreviews.com
From that second pic of Optimus coming through the smoke, the trailer has to play some role in the movie. I don't think he's going to use it as transport. It's going to be for some kind of fighting. Whether he combines with it or uses it as some kind of missle launcher or something.
Was that confirmed ? I haven't followed every devlopment so probably old stuff, but never saw mention of this before. IMDB is not necessarily accurate either...