MP Rodimus can transform from Hot Rod to Rodimus Prime. The limbs elongate to make the robot taller, and the face can change to look older as Rodimus Prime. The robot itself transforms into Hot Rod's car mode which can plug into the trailer with a faux front to make him Rodimus Prime's truck mode.

So without the trailer, Hasbro's MP Rodimus can transform between Hot Rod and Rodimus Prime forms in robot mode, but only transforms to Hot Rod's vehicle mode.