“Metaphor is the trope of resemblance par excellence” says Paul Riceour, and adds that for Aristotle metaphor is 'abbreviated simile'.
“I heard a scream of brakes” So, the actual noise of the brakes is replaced by a human noise. The actual noise resembles the human noise. Hence, the metaphor posits a resemblance. But although the actual sound may be like a scream, what the metaphor does, and perhaps more importantly and more invisibly, is transfer an affect – i.e., fear, the startle and shock when we hear a scream, the sense of imminent danger. It seems to me that the transference of an effect or affect from one thing to another is typically more significant than the claim to resemblance. To take a couple of commonplace examples. You sit down to mark a pile of exam scripts and say “i’ve got a mountain ahead of me”. This is not so much an ‘abbreviated simile’ asserting that the paperwork is like a mountain, in terms of positive attributes (very high etc). Instead, it invokes the slog, the sense of concealed heights successively emerging, of seeming impossibility, involved in scaling a mountain. Or again: “On leaving the house i was ambushed by the smell of urine.” We are not comparing urine to a band of robbers in terms of predicates or properties. It’s the sense of recoil, unpleasant and sudden surprise. It’s that affect, that reaction that we’re trying to isolate. The emotion associated with one object is "carried across" to another. To call someone a reptile, doubtless, is largely about communicating the particular kind of repulsion he/she provokes, less than the attributes of the individual.
If metaphor isolates certain perceptions, effects, affects attached to an object and transfers these to another, all this in turn presupposes of course that objects are pre-inscribed with accompanying affects, perceptions, and corresponding reactions. Objects are packets of sensations and responses, which is why the description of an object is almost always an invisible outline of an emotion or state of mind.