Vehicle parts left amid tools (5)
I believe the answer is:
axles
'vehicle parts' is the definition.
'left amid tools' is the wordplay.
'left' becomes 'l' (common abbreviation).
'amid' is an insertion indicator.
'tools' becomes 'axes' (axe is a kind of tool).
'l' going within 'axes' is 'AXLES'.
(Other definitions for axles that I've seen before include "Wheel shafts" , "Wheel rods" , "Shafts of wheels" , "Rods between wheels" , "Shaft on which wheels rotate" .)