Get back in gear somehow (6)
I believe the answer is:
regain
'get back' is the definition.
(I've seen this before)
'in gear somehow' is the wordplay.
'somehow' indicates anagramming the letters.
'in'+'gear'='ingear'
'ingear' is an anagram of 'REGAIN'.
(Other definitions for regain that I've seen before include "Take back (the Ashes, for example)" , "Recover - in gear (anag)" , "Recover, retrieve" , "Get back, recover the use of" , "Possess once more for regina" .)