He is the bad-ass weapons specialist of the Autobots, and his alt form is a GMC TopKick c4500. He has more guns than a small third-world country, and he may or may not have blown up a planet with said guns.
Ironhide doesn't always see optic to optic with Optimus Prime, despite their friendship. He's perhaps the more practical of the two, and more than a little trigger happy.
Ironhide:"You have a rodent infestation. Shall I terminate?"
Sam Witwicky:"No! No! He's not a rodent, he's a chihuahua! This is my chihuahua! We love chihuahuas, don't we?"
Ironhide:"He's leaked lubricants all over my foot!"