At 01:02 PM 6/3/2015, OlRivrRat wrote:
>         AnyOne care to discuss just what might cause the Spacer to
> Wear Shorter ~

Whatever moves against another surface will wear, evenly or with one
sacrificial to the other (paradixically, the harder surface tends to
sacrifice to the softer).  I  don't see the spacer as being in any
particular danger unless its composition is such that it moves and
wears preferentially to everything else in the assembly, which could
be.  Even so, I think that the splines getting beaten up on axle and
hub will be the major issue, not longitudinal wear.  Ideally those
splines would exist only as a safety backup, but whether or not that
applies here impact loading on them has to be kept to a minimum so
they don't beat each other out of shape. leading to an accelerating
cycle of increasing clearances leading to increased impact loads.  It
would be simpler if they were loaded only in one direction, but they
have to handle decelerating and reverse-gear loads as well.

Yours,
David