Gear required with reference to tee shot (9)
I believe the answer is:
overdrive
'gear' is the definition.
(I know that overdrive is a type of high)
'with reference to tee shot' is the wordplay.
'with reference' becomes 'over' (I can't explain this - if you can you should give a lot more credence to this answer).
'to tee shot' becomes 'drive' (I've seen this in another clue).
'over'+'drive'='OVERDRIVE'
'required' acts as a link.
Can you help me to learn more?
(Other definitions for overdrive that I've seen before include "Work too hard" , "High gear; excessive activity" , "Extra-high gear" , "State of excessive activity" , "State of high activity" .)