Crack found in sled in several cases? (7)
I believe the answer is:
luggage
'several cases?' is the definition.
'crack found in sled' is the wordplay.
'crack' becomes 'gag' (I've seen this in other clues).
'found in' is an insertion indicator.
'sled' becomes 'luge' (luge is a kind of sled).
'gag' placed inside 'luge' is 'LUGGAGE'.
'in' acts as a link.
(Other definitions for luggage that I've seen before include "Travelling cases" , "(Traveller's) suitcases" , "Cases etc for travel" , "Suitcases and travelling bags" , "Travel bags" .)