Pulling vehicle back into complex (8)
I believe the answer is:
traction
'pulling' is the definition.
(thesaurus)
'vehicle back into complex' is the wordplay.
'vehicle' becomes 'cart' (cart is a kind of vehicle).
'back' is a reversal indicator.
'complex' indicates an anagram.
'cart' back-to-front is 'trac'.
'into' anagrammed gives 'tion'.
'trac'+'tion'='TRACTION'
(Other definitions for traction that I've seen before include "Continuous pull on limb in medical treatment" , "Which leaves on the line will affect" , "Pulling - into cart (anag)" , "Grip - rat in cot (anag)" , "Act of pulling" .)