A Slipping Yanmar KM2P-1 Gearbox

This Yanmar KM2P-1 gearbox has been slipped because it was stripping or was that stripped because it was slipping? Anyway in this instance the ahead gear was the problem. Once all the component parts were laid bare, Ross discovered the gears had a mirror like appearance which signified extensive polishing. Both the ahead and reverse gears were relapped and settled back inside the cone for a successful job.