Where gear oils
are in contact
with rubber gaskets, seals, etc.,
the action of the
fluid on the rubber compositions
is of importance. Consequently a Federal
Test Method, 3604-T, has been set up. Such a test can
be varied as to temperature, time and the polymer
composition tested depending
upon the actual
service conditions of the gear
oil.
Thus, for ATF the following
procedure is used. Sections of piston seals made from Acadia 3612 rubber
compound are subjected to hot transmission fluid. Measurements of volume and
hardness are made before and after the test. Two seals are
cut into eight
sections each and the
sections are suspended
in test tubes
containing the lubricant and held
in a bath at 300 degree F for 70
hours. The sections are then
cooled for thirty minutes
to one hour in a fresh
portion of the test fluid maintained at room temperature. After wiping dry, the final
volume and durometer readings are taken.
