Part of car transport cost after European articles (13)
I believe the answer is:
undercarriage
'part of car' is the definition.
(part of a vehicle)
'transport cost after european articles' is the wordplay.
'transport cost' becomes 'carriage' (carriage means the cost of carrying).
'after' means one lot of letters go next to another.
'european articles' becomes 'under' (un and der, articles in French and German).
'carriage' after 'under' is 'UNDERCARRIAGE'.
(Other definitions for undercarriage that I've seen before include "part of plane" , "Aircraft's landing gear" , "(Aircraft) landing gear" , "Aircraft support" , "part of the aircraft" .)