yes it is possible to rebuild. However it would be had to put a cost on the repair without looking at what needs to be replaced. There is axles, axle seals, axle bearings
ring gear, pinion gear, pinion bearing, pinion seal, spider gears, gear case, main bearings. It is usually cheaper to replace the rearend with a used or rebult unit from like ( Jasper ) then it is to buy all the new parts and pay labor to install.