R_O_M
Guest
Same happened on our R62 some years ago. The later R series have wider gears but there is not enough shaft length to fit these on the earlier R series. We replaced both gears as the broken teeth or the reason for the teeth breaking may have fatigued the OK looking gear teeth and further trouble could be in store if you only replace one gear. Reasons for the teeth breaking could be any of a number; ie; constant repetitive cyclic loadings, an object going through the accelerator rolls, mistimed accelerator rolls, stones thrown up by the wheels into the gear teeth and etc.