Change gear with uranium implement (5)
I believe the answer is:
auger
'implement' is the definition.
(auger is a kind of implement)
'change gear with uranium' is the wordplay.
'change' indicates anagramming the letters.
'with' is an insertion indicator.
'uranium' becomes 'u' ('U' can be a synonym of 'uranium').
'gear' with letters rearranged gives 'ager'.
'ager' placed around 'u' is 'AUGER'.
(Other definitions for auger that I've seen before include "Boring-tool" , "something that's boring" , "Tool for boring holes in wood" , "Boring instrument" , "A drilling tool" .)