Front Differential
 

2008 Trailblazer LT 4x4 4.2L six

I pulled my front drivers side axle to swap with a new one and noticed that the seal was tore all to crap. I haven't removed the bad seal yet, but I noticed inside just ahead of the seal there is a needle bearing and a Timken bearing directly ahead of the needle bearing. What is the needle bearing for being dead next to a Timken bearing??