After it has been assembled, {HEAD ~ gearbox actuator} 30 is placed upon {TAIL ~ gearbox housing} 31 and is attached upon it, i.e., it is screwed together with it 
After it has been assembled , { HEAD ~ gearbox actuator } 30 is placed upon { TAIL ~ gearbox housing } 31 and is attached upon it , i.e. , it is screwed together with it
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH