Trouble as wrecked Argo ships gallons (5)
I believe the answer is:
aggro
'trouble' is the definition.
(short for aggression or aggravation)
'wrecked argo ships gallons' is the wordplay.
'wrecked' indicates anagramming the letters.
'ships' is an insertion indicator (to ship can mean to carry or transport something).
'gallons' becomes 'g' (abbreviation).
'argo' is an anagram of 'agro'.
'agro' going around 'g' is 'AGGRO'.
'as' acts as a link.
(Other definitions for aggro that I've seen before include "belligerence" , "Difficulties (sl.)" , "Nasty behaviour" , "Hostility" , "Aggressive, violent behaviour in short" .)