Drive shaft question...

[Mirage]

I have a '96 B2300, extended cab type. I was just looking around under my truck (mainly looking at sway bar bushings etc.) and I grabbed the drive shaft while I was there to check u-joints. Then I looked at the center bearing. I noticed I was able to move the shaft and the bearing about 3/8" in any direction. My question is, is this normal?

I'm not familiar with how this assembly goes together, (i.e. bearing, rubber insulator etc.) so any info would be helpful. My Haynes manual bearly touches on the subject.

Thanks for the help!