Взято с Answers.com из описания Thundercracker'a
After Galvatron's death, Thundercracker, in an attempt to continue being active, allied himself with the Autobots by taking part in construction work on Earth. He wanted to be an Autobot and never lose. He was forced back to the Decepticon ranks by Thunderblast, Dark Crumplezone and Ransack, who self-declared themselves as the new Decepticon army.
Если кому-то непонятно - говорите, переведу. Но, думаю, смысл понятен.