Wheeljack

Only their one small fragmentary band left, but they lived, and Soundwave and Wheeljack were among them: the two surviving Cybertronians who had mastered the infinitely complex skill of sparking new life.

[...]

“You really are an idiot,” Starscream said. “You think the entire city can transform? Where did you get that brilliant idea?”

“From the transformation cog that I found in the control center,” Cyclonus said. In the moment’s silence that followed, he drew out the fragment he’d enclosed inside his subspace compartment. “I could not take all of the device away, but I attempted to remove a section substantial enough to force them to reconstruct it from scratch—”

Hook lunged forward to snatch it from his hands, holding the segment up in the air in front of him: his optics were shining vividly as his processor rapidly dissected the circuitry patterns and interwoven quantum fibers. “Well?” Megatron said.

“Oh,” Hook said. “Oh. It’s magnificent. Oh, Wheeljack’s outdone himself…”