Director on trips took seat with truck swinging round (6)
I believe the answer is:
satnav
'director on trips' is the definition.
(a satnav gives directions when travelling)
'took seat with truck swinging round' is the wordplay.
'took seat' becomes 'sat' (to sit is to take a seat).
'with' means one lot of letters go next to another.
'truck' becomes 'van' (van is a kind of truck).
'swinging round' says the letters should be written in reverse.
'van' in reverse letter order is 'nav'.
'sat'+'nav'='SATNAV'
(Other definitions for satnav that I've seen before include "Driver's aid" , "'Guidance system, in short (3-3)'" , "Talking road map?" , "Modern substitute for a map" , "Device for finding one's way" .)