axle making bad noises

[TreeClimber]

Stay away from Synthetics, they're just not great for diffs. The best gear oil we've seen is Lucas 85-140 Mineral (petroleum based).

Digger,

I got my HD covers for my 60s, time to fill 'em up with fluid. This good for the break in period, or should I just buy generic and change it in a few hundred miles?

Thanks.