The following information is from Castrol Tech Support:
Castrol HYPOY C Gear Oil was renamed in Nov. 2011. The new name is "AXLE LIMITED SLIP" The 80W-90 Quart part number is 12612
Castrol changed the name to fit with the global marketing. I was told the specifications are 100% the same as the old name.
O'Reilly carries the product, at least here.
On sale 5.99/qt.
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