Run out of gear for a short period (6)
I believe the answer is:
streak
This might be a double definition.
'run out of gear' is the first definition.
(I've seen this before)
'a short period' is the second definition.
'streak' can be an answer for 'period' (thesaurus). I'm not sure about the 'a short' bit.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for streak that I've seen before include "Sudden flash - run naked in public" , "'Sudden flash, of lightning say (6)'" , "Long thin mark" , "Run naughtily nude in public" , "Unbroken series of events" .)