Dr. Cogwheel is "somehow" of Arachnicon stock. Her slender body is multi-armed and fine of limb with delicate probes and eight eyes. Her natural precision and finesse using multiple limbs at once made her excellent at micro-surgery and her ability to spin meshsteel webbing made her invaluable in dressing the wounded.
Dr. Cogwheel worked alongside Junior Medic Ratchet in an Iacon medical center before the Quintesson Invasion of Cybertron. When Ratchet discovered an alien device implanted in a patient named Coldwelder he called Cogwheel in for a second opinion. She was very quick to realize how ill-prepared Cybertronian society at the time was for alien contact or invasion. Ratchet felt guilty about passing the matter off to her to deal with.
Later, during the opening stages of active resistance against the Quintesson occupation Cogwheel and Ratchet designed special shackles and gags to restrain the Quintesson "emissary" guards around the Well of All Sparks they then intercepted the newest "birth" from the Well, Silverbolt, and proved medically that the T-Cog was a natural part of Transformer biology that let them change shape and not a Quintesson gift.