Differential failure

[JGraf]

Hi all!
  Well my trusty 1970 N600 finally broke, and I'm soliciting advice. I'd like to keep it original with the non-synchro trans, but I'd also prefer to only do a repair one time. In a Novelty News Miles recommended replacing the gearbox internals with parts from a later synchromesh car. Is this recommendation still valid, or can an early differential last? The other problem was that occasionally it would shift into reverse when second was the desired gear, at other times second was very reluctant to engage so maybe changing to later internals would solve that problem as well.
  Reverse always "ticked" since I've owned it, the reason is now apparent. And for many years there was a problem I felt was wheel and tire balance, yet the balance was OK, it may have been missing differential teeth. Amazingly it was driveable until one tooth finally completely disappeared. I was able to drive 15 miles home (gently) and since it was only making noise in fourth gear I felt the gearset for fourth gear was the problem.
  Once again, what would you do if you had to make this choice? Restore or improve?
Ken

[Miles Chappell]

Hi Ken et al,
I just built a non synch motor for my new sedan, I actually like the non synch type.
They will last if you spot weld together the 2 differential halves. In my theory, the
bolts loosen holding the 2 halves together and things get sloppy and sideways causing
the trans to break.
At least that is what I have seen in all the failed transmissions I
have dismantled.
Ken, if you need some gear parts you can have for free for shipping costs. Just contact
me off list z600miles @ comcast.net
Miles