What is this?

See anything unusual in this picture? No...not the fact that the pinion is destroyed from incorrect shimming. If you looked closely, you might have noticed that the pinion has nine teeth and ten splines to mate with the coupler. Guzzi never made a 9:34 x 10 gearset for regular production. Dr John commissioned a small batch of 9:34 and 6:32 gearsets with 10 splines instead of the normal 20 splines. I tracked the source of this down to a well known MG race team who shall remain nameless. They obviously didn't know how to shim a rear drive.