Shout after covering each kilometre, making harsh sound (6)
I believe the answer is:
creaky
'making harsh sound' is the definition.
'shout after covering each kilometre' is the wordplay.
'shout' becomes 'cry' ('cry' can be a synonym of 'shout').
'after covering' indicates putting letters inside.
'each' becomes 'ea'.
'kilometre' becomes 'k' (this could be a standard abbreviation of which I'm unaware).
'ea'+'k'='eak'
'cry' going around 'eak' is 'CREAKY'.
(Other definitions for creaky that I've seen before include "making grating sound" , "Giving a little sound" , "Could describe a loose floorboard or arthritic limb" , "Like an unoiled hinge; badly performed" , "Old-fashioned (and unoiled)" .)