Crib, too, became mechanical (7)
I believe the answer is:
robotic
'mechanical' is the definition.
(I've seen this before)
'crib too became' is the wordplay.
'became' is an anagram indicator (I've seen 'becoming' mean this).
'crib'+'too'='cribtoo'
'cribtoo' with letters rearranged gives 'ROBOTIC'.
(Other definitions for robotic that I've seen before include "Unthinking, like a machine" , "Mechanical; unemotional" , "Automaton-like" , "Of or using automatons" , "Stiff, unemotional" .)