W-Body's are known for hub assemblies. Normally anywhere from 75-100k. Yours did go out prematurely maybe because of the 20's but also from bad parts. I had to have both front hubs replaced on my 08' Impala SS at 13k. On my way to work I noticed a loud humming/ grinding and knew it sounded like a bad bearing. When they looked at it (I work at a dealership) it turned out both fronts were bad.

 

i have had my right hub bearing and my half, and input shafts replaced on my 08 gxp and i only have 20k