He is best friends and partners with Knock Out.
He is also Bulkhead's rival due to an unknown event.
In the episode Operation Breakdown he was captured by a human terrorist organization called M.E.C.H. Wishing to learn from his parts they began to dismantle him starting with his eye. Before they could do anything else Bulkhead came to rescue him. Starcream arrived later on and ordered him to attack Bulkhead. He was hesitant but eventually attacked.
His eye could not be replaced apparently and he was given a patch to cover his socket. This would force him to become the subject of humiliation and permanent defeat.
In the episode, Crossfire, Breakdown was sent by Megatron with Dreadwing on a mission to terminate Airachnid. Despite admitting earlier that he was "intrigued" by her, Breakdown was the first to attack Airachnid. She managed to lure him into a trap where she sliced into his body and decapitated him. This presumably killed him and his remains were captured by M.E.C.H.
Later, M.E.C.H used his body to create a shell and life support system for their mortally injured leader, Silas.
- Breakdown was originally intended to be Lugnut before being dropped & replaced by the said Decepticon due to the show creators wanted a land-based Decepticon instead.