MF, rip the bolt with the phillips head out - that is the grease port on the gearbox (most trimmers have them).
Probably ran too hard and too long without grease in the box and chipped a gear tooth.
Very standard gearbox - aldi, gardenline, pope, 909.
I personally would be more inclined to ditch the trimmer head and buy a chainsaw end for it and make it into a pole chainsaw. How many teeth is the output shaft? or is it 4 edge flex cable?
