Hope Novak gave you an answer. It's been a long time past
since I rebuilt my SM420 Sharon so don't ask me to elaborate.
But from what I do remember, the 2nd speed syncro brass is an
integral part off the first gear slider, not serviced separately
as far as I know.
http://www.pbase.com/dennygraham/image/137529622 The 3rd-4th clutch brass is the only syncro part that is supplied
in the kit.
http://www.pbase.com/dennygraham/image/137529594The inside of my SM420 was in fantastic condition so it really
didn't need to be rebuilt but since I had it out when rebuilding
the 216 I freshened it up anyway. In other words, the old
syncro brass was still in great shape and it was still
shifting just fine. An SM420 doesn't take to speed shifting
because it takes a little longer for the syncros to grab the
large gears and bring them up to speed, compared to lighter
transmissions with smaller gears having less mass.
You've been running yours for a couple of years you say, so
this may not be of any interest to you. But after my rebuild,
I refilled with Synthetic oil thinking new and improved
lubricants would be better, mostly because Ken says that's
what he runs in his trucks in his commercial operation. I had
shifting problems right of the bat. The syncro clutches
didn't want to grab so the gears didn't want to play catch-up.
My thoughts were, that with the mass of the large gears in the
SM420 there simply wasn't enough friction with the lubricity
that the synthetic oil offers. I went back to the plain old
gear oil and haven't had problems with it since.
Denny Graham
Sandwich, IL
