Rear end questions - rebulid

Hi,

I have taken our 8 3/4 axel apart and had new bearings put on the axels.

The axels are back and now I should be putting all back together.

Do I do any cleaning except for wiping off the old grease in the ends and stuff in the housing ? Do I spray the gears with anything ?
How much oil goes back in ?

Thanks
Grassy