Silverado 2500 4x4 rear axel rebuild threads?

[Bogo]

I have a 1999.5 Silverado 2500 4x4 pickup that spewed out the oil in the rear axel while towing a heavy load. Before I knew it it was humming so I need to rebuild it. I have the large sized pumpkin with a limited slip differential in it. Anybody know of rebuild threads anywhere? I've looked, but haven't located any in all the chaff out there.

I replaced the gasket and refilled the differential as a quick stop gap, but it still hums when the truck is unloaded.

 

[Bogo]

BTW: It turns out the gasket wasn't at fault. The rear cover plate rusted through at a spot where the ring gears splatter oil on it. Hence it emptied out relatively fast.