Hi John,
Its a pity you are so far away. I have a Diplomat which has not been started for 20 yrs but the drive still worked last time I used it. I would have happily given the whole thing to you. Transport costs make it all theoretical and, of course, a 40 yr old gear might fail the first time you used it. It actually worked quite well when I used to bother with it but my lawn is only good enough for a rotary mower these days.
All the best
Jeff