Go onto the hard shoulder in sweater (8)
I believe the answer is:
pullover
'sweater' is the definition.
(I know that pullover is a type of sweater)
'go onto the hard shoulder' is the wordplay.
'go' becomes 'pull' (pulling is a kind of going).
'onto' says to put letters next to each other.
'the hard shoulder' becomes 'over' (I can't justify this - if you can you should believe this answer much more).
'pull'+'over'='PULLOVER'
'in' is the link.
Can you help me to learn more?
(Other definitions for pullover that I've seen before include "top gear?" , "Sweater or jumper" , "Jersey" , "Woolly" , "Knitted garment" .)