Personal vehicle has transformed top jailer (6)
I believe the answer is:
captor
'jailer' is the definition.
(I've seen this before)
'personal vehicle has transformed top' is the wordplay.
'personal vehicle' becomes 'car' (I've seen this before).
'has' indicates putting letters inside.
'transformed' indicates anagramming the letters.
'top' anagrammed gives 'pto'.
'car' going around 'pto' is 'CAPTOR'.
(Other definitions for captor that I've seen before include "Guard" , "Someone taking prisoner" , "One imprisoning another" , "this one may have led some into a trap" , "One confining another" .)