Vehicle conks out in top gear (7)

I believe the answer is:

cardies

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'top gear' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'vehicle conks out' is the wordplay.
'vehicle' becomes 'car' (car is a kind of vehicle).
'conks out' becomes 'dies' ('die' can be a synonym of 'conk out'**).
'car'+'dies'='CARDIES'

'in' acts as a link.

Can you help me to learn more?

I've seen this clue in The Telegraph.

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