Team, recently pulled a gearbox to replace my noisy one. On disassembly found that gears one two and three have had teeth taken off at various spots on the synchros. First gear had ten teeth, five knocked off, ten good teeth, five knocked off. Second had three missing at both sides. These have obviously been taken off by hand, not mechanically, although there is evidence of grinding. Is there any old school reason for doing this? Selector hook had been welded as well. Box was in particularly good condition regarding bearings and cleanliness etc so don't know what to make of it. Hope someone may be able to help.