Bearing problem on 7 1/4" rear end

Has anyone else had axle bearing problems on the little rear ends? I'm only getting around 5k - 10k miles on the axle bearings, they split around the circumference. This is a stock slant with a 904 and 2.76 gears. Before anyone tells me to replace it with a n 8 3/4" I want to say there must be a reason other then a light duty rear that's causing these failures.