We don't have synonyms for rattle trap yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are rattletrap and rattle top.
(n) :
Alternative spelling of rattletrap. [(informal) A mechanical device, particularly an automobile, that is worn out, run down, or mechanically unreliable as indicated by noises it makes in operation.]
(n) :
Alternative spelling of rattletrap. [(informal) A mechanical device, particularly an automobile, that is worn out, run down, or mechanically unreliable as indicated by noises it makes in operation.]