transfer case radial seal

[supradupe]

How often does this seal need replacing? it's #2 in the picture. I replaced the center support bearing and now I have a very small leak coming from the neck of output flange (#3). I am wondering if this is just a coincident, or that I didn't align the center bearing correctly. There is only one position for the bearing support to be bolted to the frame. I am a bit at a lost.