Deal with jam maker (7)
I believe the answer is:
traffic
I believe this clue is a double definition.
'deal' is the first definition.
(to traffic something is to sell or deal in it)
'jam maker' is the second definition.
(as in a traffic jam)
'with' is the link.
(Other definitions for traffic that I've seen before include "that may be in jam?" , "Commerce; transport" , "Vehicles collectively" , "Vehicles moving on public highways" , "dealings" .)