Customer service 02 42571230
CLICK IMAGE TO ENLARGE IT.
Diff air vent for the upper side if most all GM diffs in the last 50 years.
Used on Diff's, Auto Transmissions.. some fuel evaporation canisters & fuel systems.
Not all cars used this size.. different diffs used different sizes.
Measuring seems to be the only way to be sure.
Choose sleeve size that inserts into the item:
Size is: 11.2mm or 9.25mm / 3/8" lower sleeve