Transformers Cars Facebook page seems to have provided the first look at Grimlock's potential robot mode. It could be another robot but the spiky, bulky look does seem very Grimlock-like. Much like with Optimus Prime with his sword and shield, this one uses maces as weapons. This is the first report of a crew hoodie with TF image on the back (I would assume people around the set would have noticed it by now) so while it could be real, it could also be a fan mock-up. As usual time will tell.