I have had similar experience with my 99 imp/outback. Dealer replaced and 48k later problem came back! So, rather than lay down another $500, I decided to do myself. Inspecting the new bearing revealed a low quality grease......so, I repacked it with Justice Brothers GC-LB. Part number 6073.Also, I made a press fixture so that the inner races were pressed gently onto the hub shaft. Also did the same for the outer race by removing some material from the old bearing race and using it to press in the new bearing.. My bearing R&R lasted 180,000 miles before replacement was required...not bad for a Subaru Noobie! Oh, the "new replacement bearing seems only to have a bit of relief cut from the outside/middle section of the race that is pressed into the hub....only difference I can see. I really feel that improper/lack of lubrication is the cause of the rear wheel bearing failures. I have only seen4 failed bearings, but all had the outboard bearing dry of lubricant. Hope this info helps others...I found out the hard way.