Ironhide

Ironhide was one of the first Autobots created to combat the Decepticons, and is Optimus Primes oldest friend.   

Ironhide was one of the first Autobots to leave Cybertron with Optimus Prime aboard the Ark , and was one of the first Autobots to be relieved millions of years later. 
Ironhide is as loyal and decent a being as any of his fellow Autobots, being older however, has given him a bit of a grumpy streak. 

His fellow Autobots and human friends are more amused by his cantankerous nature than anything else, as they know for all his reminiscing about the golden age of Cybertron and his previous battles, Ironhide will never let them down.   

Ironhide is incredibly stubborn at times, and on several occasions, even though badly damaged, has tried to continue fighting alongside his friends, even though they have told Ratchet to take him home and repair him.   

Ironhide was originally a hatch-back van coloured red.   

In transformers energon, Ironhide was a battle 4x4, though this is a much younger and not as grumpy version of him.   

In the 2007 movie, Ironhide was a GMC Top Trick truck.