We did have one issue with the Dana 60 rear axle. After about six months it developed an annoying leak at the outer drive flange plate. We replaced the oil seal on the back of the wheel hub, but found some months later that oil was seeping out of the axle again. A closer look this time during disassembly revealed that there was weld splatter bits on the spindle where the seal rode. This was cutting into our oil seal over time. We removed the offending material, installed a new seal, and the axle is holding oil fine now.