William,
My email has been bouncing LML messages recently. I saw your question on the archive list.
see page 10 here
The above describes the extension failure mode in a 320/360. I haven't studied the Legacy system relative to this failure mode -may or may not be applicable. Do you have pressure gauges? The readings during gear extensions and especially during this failure would be most helpful in identifying the cause.
Chris Zavatson
N91CZ
360std
www.N91CZ.net