Problems with Old Circuit Breakers

we have an H/ZC-17-06-25 SF6 15kV Circuit Breakers for our distribution system. however, we have encountered mechanical problems in its charging mechanism. as we did further investigation, it was found-out that the gear were already worn-out (11 of its teeth specifically). with this, i am hoping that experts here could at least guide me to possible supplier/s who can provide; either the whole package of the charging assembly (Motor + Gear + Housing) or the Gear alone. i could provide the specifications later if there are any. links will do. thank you

P.S: the switchgear was installed sometime in 2000, long before i started working at my current employer.