Using a hammer to disassemble STIHL grass trimmer, brushcutter or clearing saw gearbox can destroy it.

Pullers:
59108904407
59108904408

Gearbox grease:
07811201118

This specific model needs 9.5 to 9.8 grams of grease.
Do not mix old grease with a new one, because old grease viscosity is unknown, it might be contaminated with water and metal particles.
Do not use some random ass grease, because grease viscosity might be incorrect.
Too high viscosity grease do not lubricate enough, because gearbox working temperature is too low for this type of high viscosity grease to become fluid, which ends up with overheating and premature degrading problem.
Too low viscosity grease starts to leak out and escape from the gearbox, which ends up with overheating and premature degrading problem.