Motor probably no longer on drive shaft (7)

I believe the answer is:

sunbeam

I'm a little stuck... Click here to teach me more about this clue!

'motor probably no longer on drive shaft' is the definition.
'sunbeam' can be an answer for 'shaft' (sunbeam is a kind of shaft). I'm unsure of the 'motor probably no longer on drive' bit.

'drive shaft' is the wordplay.
'drive' becomes 'sun' (I can't justify this - if you can you should believe this answer much more).
'shaft' becomes 'beam' (synonyms).
'sun'+'beam'='SUNBEAM'

Can you help me to learn more?

(Other definitions for sunbeam that I've seen before include "Bright shaft of daylight" , "Bright ray -- bus name (anag)" , "Ray of natural light" , "sheds a bit of light" , "Ray of solar light" .)

I've seen this clue in The Telegraph.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.