Finished run in sleazy bar, needing very high gear (9)
I believe the answer is:
overdrive
'high gear' is the definition.
(overdrive is a kind of high gear)
'finished run in sleazy bar' is the wordplay.
'finished' becomes 'over' (over can mean finished or ended).
'run' becomes 'r' (cricket abbreviation).
'in' is an insertion indicator.
'sleazy bar' becomes 'dive' (dive can mean a seedy or sleazy bar).
'r' placed within 'dive' is 'drive'.
'over'+'drive'='OVERDRIVE'
'needing very' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for overdrive that I've seen before include "State of frantic activity" , "High gear; excessive activity" , "State of increased activity" , "State of high activity" , "State of excessive activity" .)