Wheeljack is one of Bulkhead's best and oldest friends. On Cybertron, they had fought together on numerous occasions. He is strong warrior in battle and wields two Cybertainium katanas. He, like Bulkhead, enjoys a good game of Lobbing.
Wheeljack was shot down by Vehicons when he arrived on Earth. Upon landing, he was ambushed. He fights valiantly but got captured. Meanwhile, a fake Wheeljack came to the Autobot base. The real Wheeljack escaped and fought against Starscream and his forces.
When the impostor opened up a ground-bridge portal to let the Decepticons in, Wheeljack made it in first andRatchet managed to close it before Starscream could get in. Wheeljack and the imposter then faced each other in a duel and he won. The bots attached a grenade to the impostor and send him back through the portal to Starscream, at which point the explosives went off, killing the impostor and silencing him so that he can't reveal the location of the Autobot Base.
Though invited to stay, Wheeljack chose not to as he wished to continue space exploration and maybe find more surviving Autobots. He invited Bulkhead along but he declined as his team, and his partner Miko, need him more than Wheeljack needed Bulk. They said goodbye and Wheeljack, in good humor, told Miko to take care of Bulkhead else he's coming after her, and she responded by taking a snap of the two former Wreckers with her cell.
Later, when Bulkhead's brain was taken over by information containing a formula for Synthetic Energon and Bulkhead began to lose his memory, Miko used the picture she took of the two of them to try and jogged his memory, to no avail.