From: "Chris Kantarjiev" <firstname.lastname@example.org>
I've happily been using Chevron Delo Lube; it's an 80-90 non-EP
oil. Makes my gearboxes very happy. Unfortunately, one must buy it
in a 5 gallon bucket.
I've been using it in diffs, too, but have lately started to wonder
if it's the non-EP status of this oil that is causing the whine...
IMHO hypoid gears really really want EP oil; no question. This due to
the "wiping" action of such gears; the teeth of the ring and pinion
slide against each other in normal operation, rather than primarily
"rolling" against other as regular gears do..