No Whine Before It’s Time

I just bought a 1966 Barracuda, 273 twobarrel.
It is my second Mopar and the first
for me with a four-speed transmission,
and that’s what I want to ask you about.
It shifts fine except, sometimes, it is
hard to shift into reverse, although it
is mostly OK. When I back up though,
there’s a very loud whining noise. Will this
be a problem, and, if so, how should I
proceed?

The symptoms you describe are simply
artifacts of the A883’s engineering compromises.
All three gears used (only) while
in reverse are straight-cut, not helical,
accounting for the gear whine. This was
strictly cost-cutting, the thought was that
most people usually back up only a few
dozen feet, and would barely notice—or
complain. With many modern cars having
helical, or even synchronized, reverse, the
whine stands out more today. Personally,
I think it is kinda cool, like the whine from
the straight-cut gears in a 1962–’** Mopar
gear-reduction starter motor.
The occasional difficulty in engaging
reverse is caused by the need to slide
the reverse idler gear into mesh with two
stationary gears (one on the countershaft,
one on the 1-2 synchronizer slider). The
teeth on the gear edges are pointed,
which helps a lot, reducing the “failure to
engage” rate to less than 2%, but if this
should happen, just release the clutch (in
neutral) for a moment to spin the gears to
a new clocking.
If the points on the gears have
been rounded off some (by erroneous,
attempted shifts into reverse while
moving), the failure engagement rate
will increase, but I have never seen this
become enough of a problem to warrant
parts replacement.
Relax—go bang some gears!
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