Can oil leaks happen from rear end

all of above,moves to the rear so a rear end leaks not at power steering area

well, we can expect a drip or two, think about the friction it endures meshing with the gears at 90 degrees, and dividing with an additonal 'spider' gear. Think about how it cools down to ambeint temperature, then up to operating temperature...that's why the gasked on the pumpkin...is needed for compensating for thermal expansion...If you are concerned, you could snug the bolts with a small ratchet a touch...but don't create a leak!

Usual leaks are from the oil seal where the pinion enters the differential. The differential, like any enclosed gear box, has a vent out the top to relieve pressure caused by thermal expansion.