Hello gearbox problem

[DJPOWER]

i need the Serial number(dont know how its called) of the cog-wheels in the ph1 gearbox . i need to replace 2 of them(they are worn).
if someone can give me a link thats will be even better!

if you can help despite the poor language i will be grateful
thanks, jhonatan.

 

[DJPOWER]

ANYONE? PLZ