Although
the measurement we list is for the middle of the "grab"
area; the high spots between A and B towards the middle;
a more critical area is where the coupling first engages
the synchro ring (Point A and Point B). At this point
there is the highest difference in rpm between the two
parts so the wear is worse. This area tends to wear more
but also suffers from how fast the person shifts. The
faster you shift the more abuse this part and the ring
takes; and in some cases even at low mileages you will
see damage. Sure you can bang a transmission around; but
you will pay for it. Actually if you really wanted to
preserve your transmission you'd need to at least shift
slow or better yet double clutch each time you shift.
Nobody does this but people who own cars that know how
much each part costs :-) It is easy to do; but time
consuming and most people do it improperly.
Anyway;
if you look at Point A you will see that it is noticeably
flattenend on the tip compared to Point B on the other
side. This was probably previously used in the 3rd-4th
position. Fourth gear wears less since there is less a
difference in ratio's between 3rd and 4th.
The
used servo synchro couplings we have are all inspected
for this severe wear pattern and examples like this are
not sold.
Wear is normal on used parts like these; but not like on
this one.
This
type of wear makes the synchro set up far less functional
and can even make shifting hard due to the grooves
(canyons) between the raised rows blocked by
material.
Most
of the wear between the coupling and the shift forks
occurs on the fork; but we look at that as
well.