Optimus tells us about Bulkhead. Apparently he was the only Autobot who could come up with good things to say about him. (Meanies)
Optimus - "To say Bulkhead is not the most graceful of Autobots would be an understatement. Still, what he lacks in agility he makes up for in pure brute strength. With his massive claws, wrecking ball arm and sheer size allow Bulkhead to smash, crush and flatten his way through just about anything. His Earth vehicle mode is an equally powerful…and bulky SWAT assault vehicle. Despite his hulking appearance Bulkhead has a sensitive spark. While on Earth he has taken as interest in human art and music. Although his technique could use some refining."