Wheeljack is his own worst enemy. Something of a crackpot inventor, a good half of his creations blow up in his face, and that's just if he's lucky. He's simultaneously one of the Autobots' greatest assets and problems; for every successful gadget he builds, there's one which requires Ratchet or Hoist to put him (and his lab) back together. But once in a while he strikes gold, which has won him respect from even the Decepticons.
He is, however, not a complete nerd. As good as he is in the lab, Wheeljack is just as amazing on the road: there are few stunts he can't pull off, and he loves to show off his driving skills as much as he does his inventions. He is, however, a little less confident when it comes to flying, which he accomplishes using solid-fuel rocket jets in his forearms.
His vehicle mode is a Lancia Stratos Turbo (or sometimes as Mercedes-Benz E550.)