Profile: The most fearsome and powerful of the Dinobots, Grimlock would gladly usurp Optimus Prime’s role as Autobot Commander if he thought he could get away with it. For now, he’s happy to tear into the enemy Decepticons whenever he can to wait for a more opportune moment to try for the leadership.  He can be cold and merciless, and shows contempt for the weak, such as humans and even some fellow Autobots. But he is a valiant warrior and his actions command respect from all who are witness to them, both friend and foe.

Abilities: Grimlock’s strength is second only to Optimus Prime’s, and even that is arguable. In dinosaur mode he can use his powerful jaws to snap in two virtually anything that comes between them –from a 4-foot diameter steel cable to a Decepticon leg. In robot mode he wields an energon-sword which can slice a 2-foot thick concrete wall with one sweep of its crackling blade. He also uses a double-barreled self-propelled rocket launcher.

Weakness: Other than arrogance and lack of speed, Grimlock has no significant weaknesses.

It's worth noting that the Dinobots had their origins told in 2 different ways. In the cartoons, the Autobots designed and built the Dinobots in 1985.  In the comics, the Ark built them to combat Shockwave immediately after the Ark's fateful crash on earth 4 million years ago.

However, considering all of the other more recently told stories of Grimlock and the other Dinobots on Cybertron prior to the Ark's fateful crash on Earth, 4 million years ago (like the War Within storyline...).   I like to believe that Ratchet and Wheeljack did RE-build the Dinobots on earth in 1985.  That they were aboard the Ark when it crashed, just that those 5 were too heavily damaged for Teletran One to bring them back to life the way it did for the other Autobots.  That it took Wheeljack's experimental personality and intelligence programming to bring their sparks back online...   Hey, why not?!