KTMrider

So i have a 00 6 cylinder with the np 242. I also have about 3.5" of lift in the front. Some how I have gone thru 2 front drive shafts via the coupling developing a lot of play. In the process my front output shaft on my t case has developed a leak that is too large to ignore any more. I grabbed it earlier the the yoke has some play so I am afraid I need a bearing as well as a new seal.

So my questions are:
1) would I be correct in needing a bearing and is this something I can do myself?? I am not too worried about the seal, but I have found little info on a bearing change.
2) should I get a longer aftermarket drive shaft to prevent them from doing bad? I just have no idea why they go bad and yes I do grease them.

Any help would be appreciated.