97 sierra transfer case leak

[gmonly1]

Noticed some spots of fluid under my truck today. Crawled under it and found that it is coming from the transfer case where the front shaft comes out. Is there a seal there that can be replaced and how hard is it to replace. If not, what has to be done?

[2000CAYukon]

There is a seal but on my 90 K1500, it was leaking thru the shaft splines. I ended up pulling the tcase and replacing the chain and all the seals. I then used thread sealant on the front output shaft to prevent it from leaking again. That was a year ago and no leaks since.

You can see a diagram of your tcase here: http://www.rsgear.com/transfer.asp

//2000CAYukon