Just seconds in every car and truck (3)
I believe the answer is:
van
'truck' is the definition.
(van is a kind of truck)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for van that I've seen before include "Forefront as of an army" , "Front of an advancing army" , "... Morrison (singer)" , "trailer" , "Trade vehicle" .)