Doug, glad to hear it worked out. Did you notice if the metal bits in
the filter were brass or steel? If brass, you're just seeing the wear
of the synchros. If steel, well, something that isn't supposed to wear
is wearing, and you should be wary.
The problem is that the gearbox and the o/d share the same oil, but
really have different needs. The gearbox pollutes its oil with the
brass that wears off the synchros, but they usually settle to the
bottom and don't get back into the works. The o/d uses the oil both for
lubrication and as a hydraulic fluid, and doesn't have a reservoir for
the bits to settle into. That's why the filter is there and is
important, and why it's doubly important on an overdrive car to try to
match revs on shifts and keep the oil clean by frequent changes.
I recently learned that Ferraris of the late 50s to mid 60s also used
Laycock de Normanville overdrives (similar operating design but not the
same boxes, of course, given that they were pushing double the HP
through). They had lots of lubrication problems and ultimately went to
a design that isolated the two oil supplies!
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