Since the seals are located at the differential end of the axle shaft, then you would really have to suspect burr or something on the shaft itself is tearing or wearing the seal - they should really check the inner end of the shaft for some abnormality that is causing premature wear. I have sleeves in my axles that also provide an integral seal at the outer end to prevent water, dirt and debris from entering the inside of the axle tube altogether.
08 JK 23S - Colorado Jeep Club No. 204
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